The biggest problem I had was learning that turns require elevator. Not just to hold altitude like a high wing trainer, but to actual turn. While I basically knew this fact, I didn't really have it sink in until I crashed on a low speed low altitude pass down the runway. The 4* began drifting towards the flight station and I banked the plane away from the stations. Without up elevator the 4* just banked, but did not pull away from the stations. Panicked and just added more aileron which resulted in steeper bank with no turn and a sudden loss of lift and altitude. Resulted in wing striking the ground followed by cartwheel. Should have added power and up elevator with bank to pull away from stations.
Now I understand the need for elevator when attempting banked turn! With trainer it really was just bank and turn, add a little elevator to maintain altitude.
One other mistake I made was to under estimate the speed. The 4* covered a lot of ground quickly and I found myself attempting to turn around a plane that was rapidly shrinking. The 4* is no speed demon, it just is a lot quicker that the Kadet Senior I had been flying. The Kadet flew great at a leisure pace that allowed for extended flight in any direction with lots of time to react. The 4* can cover a lot of ground in a short period of time.
The 4* is actually easy to fly. It just has different flight characteristics of which you must be aware.

Good Luck
dz06