If you are a sucessful B&M poker player, then my best guess is that the reason you are having trouble online is 4 tables.

You may be used to watching and tracking the action live, but this is impossible on 4 tables. It's not too bad on 2.

Also, I just started on PokerStars, and without easily available hand histories, I find the action hard to follow. Party is much easier because they have a history window - if you blink (or snooze) you can just scroll back and see what people do. Also shows all mucked cards in a showdown.