The way I teach takeoffs is to start with just driving around the ground. Get used to stearing the plane where you want it to go. Now get on the runway, and try to go straight down it slowly. Turn around and come back. Do it as many times until you feel comfortable. Do it faster and faster. Eventually, it's quite possible that you will actually hit flying speed and simply take off with out meaning to. Don't panic, just maintain a very smooth and gentil climb.

Biggest mistakes taking off are usually related to the rudder (too much, too little, at the wrong time), or from yanking the plane off the ground and trying to climb too steaply, resulting in a stall.

The key is to go as fast as you can on the ground as smoothly as you can, then climb with as much airspeed and as little nose-up as you can get away with, don't be in a hurry to "get up there". Leave the short-roll-to-vertical-climb takeoffs to the guys with the overpowered acrobats.