The things you learn on Twitter! Cribbage fiend and tournament player Chris Parsons has a great blog all about cribbage, called Planet Cribbage! Chris writes on cribbage strategy and has some great tips, for beginners and advanced players alike.
I particularly liked the article Three Levels of Thinking in Cribbage, where Chris explains how thinking deeper into the game and thinking a level above your opponent can really improve your results.
For advanced players, also check out Cribbage Tells: Five Ways Your Opponents Reveal Their Hand - how to work out what's in your opponent's hand from their mannerisms and the cards they play. If you can master this psychological level of cribbage (and hide your own tells) you'll definitely be a better cribbage player!