Thanks, folks! Having time to really work on buoyancy is one of the things I'm looking forward to. I don't have a lot of experience, but on each trip I've been pretty consistent. In Cozumel our dive master (Alejandro Salas, wonderful DM!) tried helping me to reduce my weights but I kept popping up at the end of dives.
I'm assuming more experience means more confidence, less weight?
Breathe out and change your breathing pattern before "popping up" happens. Assuming you're properly weighted, of course: you need what you need.