In a word, practise.

There are a few seconds where control is critical - and it varies with each model, but basically it's when the tail is up, but there is not much air flowing over the rudder.

One thing you can try is to use less power on take off. After all, this is not a race, so don't try to blast the plane into the air. Try doing a take off at 3/4 throttle next time.

And when you do make corrections, make them slowly. Don't jam the sticks to one side ir the other, gently ease them to each side - even if it meand going off the runway a bit. It's sort of like driving a car - If you're heading off the road, it's better to turn gingerly and go onto the shoulder a bit than to crank the wheel and flip the car over!