My skill set is pretty much complete (apart from loop passes which I am terrible at). What I do like to practice though are game specific skills. For example when I owned my Addams it had quite a lively Chair kickout so I practiced drop catching and then immediately shooting the Bear ramp. Similar thing on CSI from the scoop kickout.
So while not practising skills I will constantly look at ways of taming the ball using my skills for a particular game.