It might be helpful to watch high level games with comments so you understand why X player made this move and that one.
That way you will begin to understand the principles of some strategies and use them in your own games.
Solve a lot of problems, that is very helpful dor your tactic vision.
Alright. Problems being the tactics trainer? Or are there other useful ones online?
Try my YouTube videos. I have a lot of amateur games with useful commentary, and Dan Heisman endorses my efforts. We work together on a lot of things to help improves everyone's chess play. you may join my video lessons group here: http://www.chess.com/groups/join?id=14246
I find that my endgame and opening theory is quite good for my rating (mid 1400's), but my middle game is severely lacking.
I have only been playing chess for around 2.5 months and have yet to truly explore the middle game tactics.
After the opening, when the position becomes more complicated, I get overwhelmed and have no idea what to do.
Like in the following game, I really had no idea what to do.
Any books or online resources would be very much appreciated.