[IKE]

First, think about your core strategies.
What would you do if no one else was on the field (i.e. dead partners and the other team stays out of your way)?
What would you do with 1 good partner?
What would you do with 2 good parners?
How would you handle a lot of defense?
These are your core strategies that you should have discussed early on in the build season. Once you have those, break them down into specific tasks/skills.
If you are a hanger, practice making a logo on your own. How long does it take? How can you make it faster? What sub task can be improved by driver practice? What sub tasks could be improved with better design?
If you have a slow hanger bot, doing full field stints may take a long time. How can you improve this? Will practice help? Should you change design or tactics? Many times you can change your tactics and practice those.

If you really want to understand the art of drilling, talk with a coach at your school that gets results. Ask them how they decide what drills to do. this will give you insight into how to dissect your game play and what drills you could benefit from. Better yet, after listening to the coach, tell them a bit about "your game" and ask them for some advice. You just might find a new fan or "Strategic Mentor".