Couple of things you could work on:

1) Remember and pay attention.
When you analyze a hand history on a forum to determine whether the right decision is made on the turn or river you will take into consideration what the action and bet sizes on earlier street indicate - if when you are playing a hand you do not memorise these actions when they occur you will be missing key information on the turn or river when it comes time to make a decision. Similarly you need to observe the board and always know what the best possible hands are that can be made on the board. If you bet, someone calls and he turns over a flush or straight when you hadn't noticed that flush or straight was possible on the board - you've made a mistake. I'm not saying betting was a mistake necessarily, but you should have considered the possibility of flush or straight before deciding to bet (and maybe sized the bet differently or not bet at all). There are two ways you can be lost in a hand - one is when the opponent does something which you do not know how to interpret - this is fine and you need to just post the hand on the forum for discussion. The other way you can be lost is if you do not know what the previous actions in the hand were and do not know what hands you beat and what hands beat you. This is very basic and something you need to get right every time.

2) Reads and getting the best of it
Play against players who play worse than you. You will only win money in the long term from people who play worse than you, so you need to be able to analyze someone elses game and determine if they play worse or better than you. You need to seek out games with weak players and avoid games with strong players (or within a game, prioritise playing hands against people that are easy for you to read and control). At any table you play at you need to know where your money is going to be coming from.

And of course read all the digest threads in the forums, post questions and hand histories for comments and devote as much time to studying the game as to playing