What do you mean by "untrained"? If you are overcontrolling, try reducing the control surface movement on the model. Also, check the center of gravity and try moving it forward just a little,
say a 1/16 or an 1/8 inch at a time to stabilize the model. Then fly in a wide open space. Trim the plane to fly straight and level. Practice flying HUGE circles, with very little control input. Next try some big figure eights, keeping both circles the same pattern. Point the plane where you want it to go, and let it go! Don't "muscle" it through maneuvers. Also, don't let the airplane get in a situation where you are panicking, trying to turn it or make it climb, because you will overcontrol it everytime! The most important thing you can do is fly! fly! fly! It takes a LOT of practice, and be patient with yourself.
Best wishes,
Bud
P.S. Remember if the plane is coming towards you, move the rudder or
aileron stick towards the low wing to level it out!