I came to this site with little to no idea what i was doing, however I thought i did haha. Reading through books taught me the fundamentals and all that good stuff. Can't go wrong w/ Harrington on Hold'em.
However, the biggest improvement in my game came from posting hands and commenting on hands in the Hand Analysis sections. There are some guys who post in there regularly who have more wordly skill than I could ever hope to obtain. You just have to be ready for some criticism but if you're looking to improve your game and learn some decent strategy then that should not be an issue.
Also there is a pretty big video thread http://www.cardschat.com/f53/index-c...-games-149137/
full of cash and tourney videos, many of which have been commented on. So that's a goldmine of strategy right there.
So I'd take a few strategies to the table and see what ends up suiting your fancy. If you're playing tourneys hopefully you mix it up at critical points in the tourney (early, mid, bubble, FT, etc).
Sorry to ramble but another point that it took me a while to learn was to play my opponents and not my cards, as cliched as it may sound it will really help your game if you can pin a style on your opponent and exploit him accordingly. Sometimes the best strategy is just to adapt to the table.