I am fairly new here myself, and it seems that most of us need work on something! There are no perfect players here. (Well, not outside of their own minds anyway!) The best place to start is to play games, then play some more games and then play some more games, and if you can learn from your mistakes you will improve.
The Tactics Trainer here is quite good, but while theory and learning openings will help in the long run, the best experience you will get - in my opinion of course - is by playing games and trying different things out... If you are worried about your rating here, then just look for unrated games.

My needs are minimal: I just need serious work on openings, middle game, and endgames - with special attention to tactics and position (perhaps some study of pawn structure would help as well).
I am looking to openings first, and need to understand on a yeomans level the stengths and weaknesses of the E4 against various defenses. I tried some blitz games and was absolutely crushed, mostly due to a lack of knowing the lines.
This is an awesome site, but a trifle overwhelming as well. I feel like I am drowning in a wealth of resources, and am in need a solid starting point - preferably something that will make an immediate difference in my game. That being said, if a basis needs to be established first, I won't shrink from the work.
Any suggestions?