What makes learning to fly an RC airplane so difficult is that we are not only learning to fly an airplane, we are also learning to control a vehicle from outside the vehicle. Have you ever tried to fix something that you could only see by using a dentist's mirror, or tried to shave or apply makeup using a video camera and TV monitor for a mirror? This will give you an idea of just how alien RC can be to someone who's been in the cockpits of full scale aircraft all his life.
If you have to learn by yourself, learn these two separate skill one at a time. Get a cheap toy RC car, preferably with a stick instead of a wheel controller, and play with it until driving it towards you is completely instinctive. Don't just blast around in a big open field, discipine yourself to stay on a road marked out with pylons.
Now that driving an RC car is completely instintive, you will be way ahead when actually trying to fly.
Airplanes do not steer like cars. An airplane turn is a combination of aileron and elevator inputs. The rudder can be left alone for now. Most beginners give the plane left aileron expecting the plane to turn left. When the plane does not immediately turn left, they figure that it needs even more left aileron and now the plane is nearly upside down and losing altitude fast. This loss of altitude causes the beginner to command it to go up by pulling back on the elevator and the upside down plane does exactly as it's told. By the time the beginner figured out what went wrong, it's too late. Another thing that's different than cars is that when you want a car to stop turning, you just return the stick or wheel to the center and voila!, the car goes straight. With an airplane, to stop a left turn, you have to give right aileron until the plane is level and then the stick can be centered.
Not realizing that you have to give opposite turn command to stop a turn leads to the beginner's "death spiral". A turn becomes a spiral dive because returning the stick to the center does not halt the turn. Pulling the elevator back in a panic only tightens the turn and the plane usually ends up being destroyed.

Have I convinced you to find an instructor yet?