I wish I had the time to set up any sort of practice routine.
What I've started doing lately, when I have a game off (meaning I just lost and someone else has taken my place at the table

) and one of the other adjacent tables isn't being used, I'll take the balls and shoot them into a pocket, 5 balls to a pocket. Usually from 2-3 feet away. I'll try to just focus on the basics, stroke, bridge, grip, etc. I'll try to mix it up, shooting straight in, draw, follow, various slight cut shots with inside and outside english (how's that Scott, got the terminology correct this time!), put 5 balls in, move to a different pocket and hit the next 5 to a different pocket, etc.
I'll do this until it's my turn to play again. 10-15 minutes, maybe a little more depending on the chatter and refreshment/bathroom breaks.
Not really structed, not consistent. But it gives me a chance to just dial in the basics. Sometimes I'll even do a little of this when my buddy and I are the only ones in the room, and he's busy running balls on me. Hell, I have the time!

I've even started to try and teach myself a more defined "Set, Pause, Finish" routine. Very much still a work in progress, especially with little to no "real" practice time, but I can see little pieces of it develop.
It's not the best practice, I'm sure. But it does help me keep the foundation of my game a bit more grounded. I've noticed some real benefit on a couple of aspects of my stroke as a result lately. Small improvement, but hey, I need all the help I can get!