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

[Hotel26]

There are two things I don't like.

1. The first thing I don't like is clutter.  For a long time, I cursed KSP because occasionally when I returned to the Tracking View, it would light up ALL the various craft types by default and show LOTS of clutter, especially relays buzzing everywhere.

I would turn them all off except the type I was particularly looking for.  Occasionally, when exiting the Tracking View (via the exit door) rather than e.g. switching to a ship, I would turn off that last type selection I had lit, so that everything was clean & tidy for the next use.

Well, that was the problem: KSP figures it is useless (and perhaps confusing) to have no types lit, so it helpfully? then lights them all for you.  Curses, KSP!! 

So now I just leave something like EVAs lit, because there are very few of those in progress.

2. The second thing I don't like is programs that make "useful assumptions and then (silently) take unilateral actions" -- such as the above.  Double curses, KSP!! 

I was indeed very happy when I solved this mystery, though.

Edited October 23, 2023 by Hotel26

[Jacob Kerman]

IF IT LOOKS STUPID, DO IT

 

[Kimera Industries]

My basic advice?

1. Enable "advanced tweakables." Autostrut will save your life. (Stick with 'heaviest part')
2. It also lets you split maneuver burn times 50-50 on either side of the maneuver, making them more accurate.
3. Speaking of maneuvers, the green double arrow on the left of the maneuver dv indicator lets you warp to just 1 minute before burn time. Works great for me so far, saves time trying to warp to it manually.
4. Don't overcomplicate things. Set a goal for your design, and meet that goal. Don't try to upgrade and go bigger and farther. You will end up biting more than you can chew and the project will fail. If you want more capability, start fresh. 
5. SSTOs- it takes a long time to get them to work. You will not get them right away. It will take you a long time. A very long time. Just because Matt Lowne threw together something in 3 minutes does not mean you can too.
6. Practice! Don't be afraid of failure. Use quicksaves, specifically Alt+f5 and Alt+f9. These let you use named quicksaves that you can load at will.
7. Revert the flight if you can't fix it. This can avoid kerbal deaths or fatal mistakes.

If I had known these things when I started playing KSP, I would have started a lot better. I hope these help someone else too!