Nut Slide

This is a lower priority suggestion regarding the runway but threshold runway markings suggest a runway width of 125'. Using speed and time calculations, the runway width is ~360ft wide. In addition, FAA publishes the runway centerline stripes to be 120ft long. Again, based on speed and time calculations, they are ~577ft long. The spacing between those are supposed to be 80ft. The lighting has some things wrong. The centerline and runway edge lighting is semi-directional for colors, not omnidirectional. Going down the runway, centerline lights are white until the last 3000ft, where they then should alternate white and red. At 1000ft before the far end of the runway, they are solid red. Runway edge light is white until the last 2000ft or last half of the runway, whichever is less and turn to yellow the rest of the way. There are other things I noticed too but since I teach students to fly planes, I figured I'd throw in some finer detailed suggestions. Let me know if you want more feedback on some of the other things I noticed with the airport.

This is a lower priority suggestion regarding the runway but threshold runway markings suggest a runway width of 125'. Using speed and time calculations, the runway width is ~360ft wide. In addition, FAA publishes the runway centerline stripes to be 120ft long. Again, based on speed and time calculations, they are ~577ft long. The spacing between those are supposed to be 80ft. The lighting has some things wrong. The centerline and runway edge lighting is semi-directional for colors, not omnidirectional. Going down the runway, centerline lights are white until the last 3000ft, where they then should alternate white and red. At 1000ft before the far end of the runway, they are solid red. Runway edge light is white until the last 2000ft or last half of the runway, whichever is less and turn to yellow the rest of the way. There are other things I noticed too but since I teach students to fly planes, I figured I'd throw in some finer detailed suggestions. Let me know if you want more feedback on some of the other things I noticed with the airport.

For such a small payload, and the fuel/engines at the lower stages, you are using a bazooka on a fly. In other words, the rocket engines you have are overkill for such a small payload. I'm guessing the TWR is really high due to using 3 Mainsail engines. Due to the distance between the center of mass (CoM) and the top of the rocket, you are probably experiencing a lot of torque which will induce flipping and when correcting the flipping motion, the rocket is probably overcorrecting since 3 mainsails are vectoring with steering input. Downsize a bit. You could probably get away with 1 mainsail and 2 reliants if you want to have two FL-T series tanks on the side. Just ensure that your Delta V is around 3500 with a TWR of around 2-3 and I think you will be fine having enough to get to orbit. I look to have my CoM slightly below the center of the rocket for launching. I have had better success using that which yielded less flipping tendencies. If it still wants to flip, add fins just above the mainsail on the bottom. Hope this helps.

Others have posted some pretty good gouge on how to get to a stabilized orbit, but I'm going to respond with my own technique. Please note that it is technique only as there is a million ways to skin this cat. Note: I HIGHLY recommend starting a science mode as a beginner or sandbox, but NOT a career mode. Science mode allows you to create maneuver nodes as a default setting without have to earn that capability. Maneuver nodes are your friend. 1. Build a two stage rocket that has two stages, each with engines. (Preferred that both engines have vectoring for easy steering. 2. The rocket has 3500 m/s Delta V(4000 m/s if you need it for practice) total with around 2.00 TWR for the first and second stages. I recommend staying away from solid rocket boosters(unless you have a third liquid fuel engine that can steer you with vectoring during the launch stage). Ensure this is verified as being used in an atmosphere, not a vacuum. 3. Next, active SAS and then Launch. At around 100 m/s, begin your gravity turn (steering) toward 90 degrees. This will save Delta V. 4. Strive to reach 75 degrees by 5000m, 45 degrees by 10000m, and then continue the turn until you reach 30 degrees and hold. 5. When the Apoapsis reaches 75-90km, cut the engine(s) off. Create a maneuver node at the Apoapsis and drag the Prograde node out until the planned trajectory is a circularized orbit. 6. Watch the timer tick down and start the burn at 1/2 the total burn time required. (Ex: if the total burn is 1 minute, start the burn at 30 seconds prior to when KSP tells you to start the burn. Burn for the full minute in this case and cut off the engine(s). This should get you close to a circularized orbit. Again, technique only. I like to play a bit conservative so I usually have a circularized orbit around 90km IF i am staying within the Kerbin system. If you want to travel outside the Kerbin system, I recommend using an apoapsis of around 80km for better Oberth Effect(don't worry about that until after you are ready to venture to other planets).