If you want to improve your squat, deadlift, bench press, overhead press, pull up, etc. I firmly believe that your best bet is to do the lift. I often marvel at how many programs, designed to improve a certain lift, shy away from actually doing the lift in question. I guess in reality it’s not that shocking. After all, everyone is looking for the next best thing. People are quick to jump at some crazy new variation, or assistance lift guaranteed to elevate their numbers. The truth is, nothing will make you a better squatter than squatting more. The same goes for just about all the big lifts.
Increasing volume means more time spent practicing good technique, more reps to groove the pattern, and more time for the CNS to develop the coordination needed to perform the lift.
Instead of seeking out new ways to improve your big lifts, just do them more often. Obviously this calls for an intelligent management of intensities and volume, but it will work.