Gotta agree with Flycatch. However, you can think too much about take offs and liftoff and all of the that. Three things you can't get more of, once you have wasted it after starting to take off;
1. more runway ( start at the very end of the down wind side.
2. more fuel (make sure your tank is full).
3. free electrons (make sure your batteries are charged and up to voltage)

Most trainers will take off nice and straight all by themselves into the wind, if your landing gears are aligned straight or slightly towed in (tail draggers).

Make sure you have plenty of ground speed to support straight and level flight before you pull back on the elevator.

Make sure your plane is properly balanced. A tail heavy plane usually lifts off before a stable speed is reached and usually tip stalls and cartwheels across the strip. A nose heavy plane may be difficult to get air bourne and land like a bat out of hedes.

I tell most beginners to use as much runway as necessary to get the most acceleration possible before lift off, then the control surfaces have enough air flow over them for good positive response.

Most trainers with flat bottom or semi wings will rise with throttle increase and decend with throttle decrease. You can control you rate of decent with the throttle, but be gentle with it. The trainer should be able to take off and land with almost no control input into the wind almost by itself, if it is properly balanced and set up.

Make sure you have an experienced modeler check it out for you to avoid many of the minor pitfalls that can add up and multiply into big problems.

Hope this helps, Happy Landings and takeoffs!