Play ABC poker!!!
Don't make big bluffs. Obviously you still bet when you have no showdown value and your opponent is showing weakness.
Always ask yourself why am I betting. What hands am I trying to get too fold and will they fold.
Don't get yourself into awkward situations
Don't play passive.
Try to play more hands in position.
Don't pay off your opponents. When they go all in or re-raise you they usually have a big holding especially in Zooom poker. Regular tables it's a bit different. You will find that opponents can do some more crazy things at the regular tables but at Zoom players usually just wait to flop a big hand.
If you have a HUD you can pretty much exploit every single player in 2NL. They always have some sort of weakness. I got PockerTracker 4 a few days ago and my win rate at 2NL just exploded through the roof.
You should probably look to do some more study on the game. Study always helps.