When I first started I thought I would have an easy time. I was chess champ at my high school, never lost in a tourney. I soon realized that it is very easy to screw up when you're trying to play 9 or 10 games at the same time. So, my ranking quickly dropped into the 900's. Since then I have slipped into that same bad habit a couple of times. It's easy to do because there are so many people to play.
If I was to give advise to a new player, it would be start slow, don't try to play too many games at once, 2 or 3 is good. Also, take your time, don't get rushed, YOU WILL SCREW UP IF YOU HURRY!!