Elyeh,
I think one of the most important things you can learn in flying (real or sims) is trim. Trim allows you to take the pressure off your controls for a given flight situation. When your plane is properly trimmed for level flight you should be able to take your hands off the controls and the plane will continue to fly straight and level.
Trim modeling in AH can be a bit touchy. Especially in some planes. AH has added some helpful tools to deal with this.
Auto Level (X): Trims your plane to level flight
Auto Angle (SHFT-X): Trims your plane to the current climb or dive angle:
Auto Climb (ALT-X): Trims to best climb speed.
While combat trim (CTRL-X) is usefull there are time when you will find yourself fighting against what combat trim wants to do with your plane. CT has a limited number of situations that it knows how to trim your aircraft. Therefor you should learn to use manual trim. If your flaps or gear is down CT will be fighting you as it doesn't account for flaps or gear. Learning to trim your plane for landing will make your landings easier and smoother.
CT is usefull to get your plane into trim quickly though. If your fairly level and not hard manuevering hit CT to quickly trim up your plane.
If you have an available hat switch on your stick map it to at least elevator trim and rudder trim. Practice trimming your plane manually for different situations. One you can try is to trim for a dive.
With a lot of altitude nose your plane over into a dive and watch your G gauge, Hold the stick so the G is at 0, apply elevator trim down while easing the stick back to the center position and try to keep the G at 0 using up and down trim, when you have your plane trimmed to 0 G you should be plumitting towards the ground.

When you want to pull out, apply elevator trim up until the G guage reads 1G and ease the stick back and pull out of the dive.
A 0G dive is the most efficient. Try this in a P47 and you will be amazed at how fast that big jug can pick up speed.
I read an article about landings once that went something like this.
Enter the pattern, speed to 175, TRIM. turn into the down wind leg, speed to 150, TRIM, Flaps to 30%, TRIM, Speed to 125 gear down, flaps to 50% TRIM. Speed to 100, full flaps, TRIM, turn to base leg, TRIM, Turn to approach, speed to 75, TRIM, Come over the fence cut throttle and land.
As you can see TRIM is very important.
As with everything in AH it's practice, practice. Don't get discouraged it will come. Remember that some of the pilots in AH have been doing this for years.