Quite a few "beginner" level instruction books I've seen stress that if you drop your pick you need to hold it a little tighter, but if you don't drop your pick, you're holding it too tight. I think this instruction is a little overblown, but relaxing everything you don't need is definitely a help.

Observation of a few good players gives me the impression that mando players tend to use the "edge" of the pick much more than guitarists. You "hang up" on the strings less if the pick is at a little angle to the strings, as opposed to just laying it flat on the string when you pull it across. I've collected a small sampling of discarded picks from a few respectable players, and the "faces" on most are almost virgin, but the edges are generally pretty heavily worn.

Experimentation, to find what suits you, is the key.

John