Here's a couple of tips. First, raw power. Use solid boosters, as many as possible. Some of my ships use 18 solid boosters and 1 of the huge liquid fuel thrusters. Yes, that's how much raw power. Then, once you get to 10 KM start turning. This is called the gravity turn and if you do so at around 10 KM you'll benefit from it. Do avoid doing so if you're still on the raw power phase. If you have lots of solid boosters burnin', it's not a good idea to turn your ship. Finally, you'll want to stay above 75 KM. That's the edge of the atmosphere, and unless you REALLY want to get back to kerbal you're better off staying above that level.