What are the most important things you've learned about playing KSP to pass on?

[Lukaszenko]

Driving my car uphill fast reduces gravitational d/V (fuel) losses! Even if it means flooring it to get up to the speed limit at the base of the hill LOL

I don't think the Oberth Effect applies to cars

[Clear Air Turbulence]

I don't think the Oberth Effect applies to cars

There's only one way to find out. I'm going to try this tomorrow.

[Saltless Lemons]

1) Learn to use maneuver nodes, but don't become dependent on them. They are super useful, but when I'm just operating around Kerbin, orbiting and heading to the Mun, I barely use them at all.

2) I like to create a checklist of everything a rocket/plane needs. I've been playing for a year or two, but I still regularly forget to include air intakes on my planes

3) Make sure you use everything. (This kinda ties in with point 1). Use the maneuver nodes as much as you want/need. Quicksave (some people don't like to quicksave/load, but on a 3 real-time hour flight, quicksaving is invaluable. I can't tell you how many times I have accidentally timewarped too fast and far towards a Kerbin reentry and crashed straight into the planet without quicksaving).

3) When your plane/rocket fails in a fiery ball, laugh. In KSP it is easy to find something funny in the most monumental of screwups. Don't forget to look for the fun(ny) side of things.

[deltalambdamu]

Use the action groups. Assign the "1" key to deploy fairings, "2" to deploy solar panels. I recently made a lander with a light under the landing struts. I set it to activate with the "Gear" action group to illuminate the ground during descent.

[Dat_Spy_44]

1.Never go too beyond Eeloo.

2.ALWAYS BRING BATTERIES!

3.Use HyperEdit to bring up fueling stations into orbit.

4.Never go full Jeb.

5.Never try to land on Jool with a large rocket at 7KM per second.

[Fraus]

5.Never try to land on Jool with a large rocket at 7KM per second.

1. Never try landing on a gas giant.

2. Never try to land on the sun either of course.

3. If your terrible at making a SSTO and can get one to Eve, don't go into Eve thinking you'll come back out if you land.

4. In general, try to keep the Kerbal flavored pudding to a minimum, unmanned tests of manned things first is usually a good idea.

[percyPrune]

unmanned tests of manned things first is usually a good idea.

... as long as you remember to add a Probe Core for control.

I even add a Probe Core to manned vessels so they stay under control during EVAs. Early experience taught me that when all the crew EVA the SAS stops and a badly landed ship falls over!

[Alchemist]

I see no reason why not to install automated control systems (probe cores) on crewed vehicles. It's the Russian way, actually: every manned vessel must have the capability to perform its mission fully automatically, but the crew must have the skills to complete (or safely abort) the mission manually in case of automatics failure.

[SpaceplaneAddict]

Spaceplanes require a minimum of 1300 m/s delta v in rocket fuel for LKO and a small margin.

[celem]

I see no reason why not to install automated control systems (probe cores) on crewed vehicles. It's the Russian way, actually: every manned vessel must have the capability to perform its mission fully automatically, but the crew must have the skills to complete (or safely abort) the mission manually in case of automatics failure.

This, so much. Apart from anything else it lets you leave the pilots at home and retain SAS locks. Most of my tourist ferries are robotic. I also then install a probe core onto the top stage of my lifters so that it can deorbit them. Also the probe core to retain SAS when the pilot EVAs is a solid tip, had several craft tip on slopes and roll over Jeb because he tried to get out.

The single most important thing I've picked up however is perseverance. Mods like KAC/KER and guides by likes likes of Mr Manley are all well and good (they really are), but you can totally learn this on your own without having an engineering background. Coming up with a working ratio of tanks:engines takes a little trial and error, if you are feeling brave you can do some sketchy rocketry equations but that just overflowed my desk with notepaper, easier to "sim" by launching a series of tweaked designs or just pick up KER, which exists primarily to do that bit of math for you.

Secondly: Dont be afraid to try some riskier mission profiles. I have a bunch of mates who in theory are quite good at Kerbal. One guy in particular is routinely able to launch directly to docking when assembling stations in LKO, but he has never landed on either of Kerbins moons or left Kerbin's SoI because his OCD is terrified of killing kerbals. Man up and throw the little green guys across space, they love it really.

Thirdly: Just dont land on Eve and expect to get your kerbal back. If you are even reading this thread seriously looking for gameplay pointers then you will not pull the return off. ONE DOES NOT SIMPLY LIFT OFF FROM EVE. (with that said its a perfect pinnacle achievement and comes with bragging rights, once you have gotten into the game then rule 2 trumps rule 3, but you were warned...)

edit:

Theres always been a very "learn to play vanilla" attitude to KSP, new users are actively discouraged from modding. This has always been too fuzzy in my mind, I would agree with not installing MechJeb or any "far-future" parts packs initially however, the parts just outperform all the stock by factors and magnitudes, you wont learn usable design skills. Mechjeb is too tempting to my mind, however he is a valuable learning tool, you really can learn to pull off some manouevers by watching him execute them, and for the advanced players theres a certain tedium removal once you are launching the 19th refueler to your station. I would actively encourage new players to try other mods however, any of the realism bits, stuff that adds depth or near-future tech, cosmetic stuff, outright utilities (navball especially). Just really really watch out for the trap of letting MJ fly it all, you wont ever get better at manual.

Edited October 23, 2015 by celem

[Gojira1000]

1 - Build light

2- Build simple

3 - Be ready to break rules 1 and 2 when it's more fun

4 - Science is easy, don't bother with the mods that add more instrumentation or you'll max your tech tree too quickly

5 - Outer Planets is a lovely mod. So is KW Rocketry if you like lofting huge hunks of junk.

6 - A lotta hate for poor MechJeb in some comments. I played my first 100+ hours without MJ, and learned how to do everything, but I have to admit I love having the little plastic case welded to my ships. It doesn't do anything better than an actual player piloting (and you have to watch it like a hawk (or usually just not use it) during launches and landings and rendezvous) but it's perfectly handy for doing a lot of the repetitive grunt-work while you go make a cup of tea. Besides, its Delta-V display is incredibly useful.

7 - ALT > and ALT < are your friends. Usually.

[Legendary Emu]

1 - Struts.

2 - If it doesn't look fly, it doesn't fly.

3 - Never land on the dark side.

4 - Bring batteries.

5 - Start your circularization burn BEFORE apoapsis.

6 - Build rockets the way God and Robert Heinlein intended.

edit: 7 - Stockalike mods to rule them all.

[Generalstarwars333]

Well, for me MechJeb lags the game to unplayability. My main epiphanies have been realizing the way to get to orbit is to get to space, then burn a ccertain way or turn in atmo if the ship is small enough for mme to not be scared by the cyan aerodynamic lines. Also, SSTO planes are easy circular orbiters. plus the way that mpl-g2s work, and how science and stuff works. that and the fact that right clicking parachutes tells you when to open thhem.

[The Optimist]

-Duna is hard to land on

-Eve sucks

-Laythe is gr8

-Modded planets are great

- - - Updated - - -

Someone has to know how to change your avatar, right?

[Generalstarwars333]

I'm pretty sure that you upload a file from your pictures to it or something...

[Red Iron Crown]

Someone has to know how to change your avatar, right?

Settings -> Edit Avatar -> Either enter an URL of an online picture or upload one from your PC.

[Eve]

I like using MechJeb, but it is really fun when I do something on my own. I think the problem-solving is part of playing KSP. However, after many successful launches getting into Kerbin orbit becomes tedious. That is when I use MechJeb. I certainly agree with radializing, and never forgetting power. Many a kerbal has died because the ship ran out of power.

[Dralon Perfecto]

When docking, you can switch to the target vessel, and bring up the right-click menu of the docking port you are aiming for. (Click 'control from here' as usual.) Leave the menu active, and switch back to the ship you are actively controlling to dock. The menu on the target vessel will still be on the screen, but the menu option will have changed to 'set target'.

This is much easier than trying to pick out and right-click on the few pixels of docking port from the active vessel when you are still some way away. (You have to be closer than 200m to select an individual docking port, but at that distance it can be hard to right click the port.)

[Venusgate]

I just figured this one out only recently, but its something ive always wondered. When your maneuvering node "collapses" into an orange circle with two gray c7rcles below it (might only happen when you have a target selected) these two circles are forward one orbit (right circle) and back one orbit (left).

This is useful in the sense that if yiu are trying to conserve dv, there might be a cheaper transfer in a few orbit, but instead of guessing, you can make a node, and click forward a few orbits until you see the seperation arrows close together (or closer than on your current orbit). Then adjust the node to zero out the seperation, and it will automatically say your node is in x time (x=time to node in current orbit+time of number of orbits for optimal transfer). No more wasteful burns when waiting a few hours would cut it in half!

[Akronymus]

Getting to space is easy. Staying there is the hard part

[JackBush]

[quote name='Eve']I like using MechJeb, but it is really fun when I do something on my own. I think the problem-solving is part of playing KSP. However, after many successful launches getting into Kerbin orbit becomes tedious. That is when I use MechJeb. I certainly agree with radializing, and never forgetting power. Many a kerbal has died because the ship ran out of power.[/QUOTE]

I agree. How does MechJeb help you get into orbit easily? Are you flying crewless and, thus, able to use auto-ascent? Or what?

[rockbloodystar]

[quote name='JackBush']I agree. How does MechJeb help you get into orbit easily? Are you flying crewless and, thus, able to use auto-ascent? Or what?[/QUOTE]

Auto ascent is available even in crewed craft.

[WildBill]

My recent discoveries (apologies if this is old news):
1. When setting up maneuver nodes, you can click on your target (say Jool), and select Focus View. Now you can zoom in and see the details of exactly how you're going to approach your target. And when you actually execute the maneuver, I do the same thing. Except this time you can make tiny little burns (with RCS) to fine-tune your approach way before you even get close. Saves lots of fuel!
2. Talking about Maneuver Nodes, gang a couple of them together. Especially with Eve, my initial de-orbit burn from Kerbin never intersects due to the different inclinations. So plop a 2nd Maneuver node at the future A/D Node and add a correction burn. Now you can go back to the 1st Maneuver Node and fine tune your burn for an optimal intersection.
3. I love the new course tracking options to the left of the NavBall, especially RetroGrade for landing. Once I get my lander pointed tail-down, I click on RetroGrade. Now the lander will automatically point straight up and Retro burns add very little horizontal drift. No more landing with too much lateral drift and flipping over.
4. When docking, once you get close, use [ and ] to switch between your target and you. If your target isn't enormous or fragile, move it around a bit to make your approach easier/straighter.

I never use MechJeb, just KER for it's wealth of information, and the built-in SAS. I just like flying everything myself...

[sdrevik]

I played LOTS of games before figuring this out:

When coming into a planet (Duna, Moho, etc) from a transfer, and you want to make an adjustment, zoom out, click on the destination planet, give it the focus, and rotate your view so when you zoom in, you can access your correction maneuver handles as well as be zoomed into the target system. It will show your trace as you come into the SOI, and you can tweak it to ensure you are on the right plane, rotating the right way to hit the moons / space stations you want, etc.

I played probably 100 interplanetary missions with nothing more than closest periapsis numbers to guide me. I had no idea I could do this, and it made life so much better. Nothing more annoying than to enter Jool and be rotating the wrong way around.

[Ehco Corrallo]

You don't always need to be at full throttle when launching a ship. As you get higher in the atmosphere, it's sometimes possible to ease off the throttle. It saves fuel and can massively increase the range of your ship. 

If you put EAS-1 seats in a Service Bay, you can make an inexpensive, ultralight lander can. 

Landing lights are useful even if you aren't coming down on the dark side of a planet. They work even better if you make them a contrasting color to the ground.