1. Never use a light or medium pick. Use at least a heavy. With a heavy, the pick does the work and takes the beating. With lighter picks, you do the work.
2. Never anchor your hand because it causes you to take your hand out of the position it needs to be in to be pain free. Want to palm mute? Stick a sponge under the strings instead. Palm muting is especially injurous, even though a lot of people do it.
3. Pick close to the neck where the strings are looser. I use light strings (.040 G) so I can pick from between the neck up to the first pickup without pain. For .045 G and higher, you're better off staying close to the neck. Yes, I know it sounds boomy up there. But it really doesn't sound as boomy as you think in a mix. If it really irritates you, roll off some bass instead.
4. Hold your hand to where your pinky is slightly raised off the strings, and keep your wrist parallel with the strings. Move your hand from the wrist in a side to side motion, and NEVER MOVE YOUR THUMB!!! Moving your thumb is a killer.
5. (OOPS...forgot this one...extremely important!) Don't play just downstrokes. Always play down-up. Downstrokes take your wrist out of the side to side movement and cause pain. "But Jimmy," you protest, "Downstrokes sound heavier than upstrokes!" Hmmm, sounds like you need to practice more. If someone can tell the difference between you playing all downstrokes and you playing down-up, just practice it until you get it.
Takes a little getting used to, but it's so much better than ending the night with your hand in an ice bucket or having surgery once a year. You may be getting away with the stuff you're doing for a while, but it'll catch up with you eventually. Trust me.
Jimmy, thanks for this information. For the last few weeks I've been studying and learning her picking tips from her website. I've always used index and middle finger, but my index finger has become arthritic and inflamed from overuse. I still prefer using my fingers to picking, though I'm hoping to get to the point where I can play easier songs with the pick and the more difficult songs with my fingers. You are spot-on when you speak of playing bass for the long haul... get the technique right and you significantly increase your chances of remaining injury free.