The right drills van be super challenging and pay off great rewards if you stick to them. Having a video camera on you helps out in not just viewing your form and fundamentals but learning from mistakes and reviewing shot decisions.
Here is a thread I started 2 years ago regarding one of the best drills that I know of.
I normally play a Ghost when I video my practise, but drills occasionally too. More drill practise when I play Snooker or Finnish Kaisa.
It is teaching so much.
Also it is proved it's power. Last Year I made my first 147 pn Snooker(with poolcue) and l've been winning everything on Finnish Kaisa(last weekend i won scotch double Finnish Chsmps ).