I’ve been using vi and vim also for some 20 years, and I’m still learning new things.
David Rayner’s Best of Vim Tips site is an excellent list, though it’s probably more useful once you have some familiarity with vim.
I also want to mention the ViEmu site which has some great info on vi/vim tips and especially the article Why, oh WHY, do those nutheads use vi? (archived version)