Remember aileron in x-winds is for side-shifting. The more aileron, the more opposite rudder will be required, or otherwise you will turn, defeating the purpose.

My set-up to really practice this is establish a 3-5nm final, or just use a road and keep some altitude. Work the ailerons, and rudder as to always maintain a parallel course to the rwy/road, but side-shift yourself left and right of course. Practice how much input you need to correct with varying winds and speeds. It will help build the feel for what it takes, just like landing flares! The rest is really just practicing, and having an instructor that's skilled enough to go take you out and do Max-Demonstrated x-wind practice. One of the best and unfortgettable lessons during my training!!!