Step 1- DO NOT play when you are stressed out. This happens all to often, someone will have a lot of bankroll on their account and be in a bad mood one day and lose it all. You have to be cool calm and collective to play well.
Step 2- Pro Players very rarely play a hand and when they do they usually are holding something good. that being said, sometimes they will sense your noviceness and try and break you.
Step 3- FOLD Often. It is never to late to fold on a hand. If your hand is crappy don't call every bet. If you are the big blind and everybody calls you go ahead and check out the flop. But if someone raises your blind and your holding an 8,3 FOLD.
Step 4- Learn what the good hole cards are. There are numerous web sites that will teach you these.
Step 5- Play for fun. Don't play to make money and quit your job, just play. if you lose money don't try to win it back you will care less and end up losing more.
Summary- With these simple steps you will be playing online poker like a pro in no time. Have fun!