Hundreds of drills can be found on the Internet (see links page) but here are some pointers to getting the most from drills sessions and some especially useful and unusual drills I have come across:
A much better routine to start off with is boasts and drives with an option to hit straight or cross-court from the front. This means that the player at the front is trying to out-fox the player at the back and the player at the back has to return at least some way to the T to carry on retrieving the ball. Better players can take this further by giving the player at the back the option to hit a straight drop from the back, meaning that the front player is them kept on his toes as well. This makes for a much better routine and demonstrates the basic concept that should be applied to squash drills.
A:boast B:drop A:cross-court lob A:boast
The best drills force both players to move through the T. That way both shots and court movement can be worked on. This drill also practices the lob, one of the most effective and under-used shots in squash.
A:boast B:straight drive A:straight drive B:boast
A good all-round drill. If you get bored, try adding a drop in after the boast.
The aim of this drill is to last as long as you can under ridiculous pressure. One rally each until knackered. Whoever wins the fewest rallies (or keels over) buys the pints. Don't do this one if you are 90 or have recently undergone major surgery.
A (left box):boast B (on T):straight drive C (right box):straight drive B:boast C:straight drive A:straight drive C:boast A:straight drive B:straight drive A:boast...
This is a great drill taught to me recently. It is hard to get your head round, but great fun when you do and it takes all three players in rotation through the T to all corners of the court.
If you know a really outstanding drill or one you think we should include here, send it in!