Wowhead and WoWWiki have plenty of information about the ins and outs of WoW (and a database of everything within WoW, in the case of Wowhead) - should give you plenty of info about whatever class you choose to level, and if you run into any problems along the way.
Try to find someone of the same class who knows what they're doing. You can learn tons, but if you're still leveling then just read the abilities. Blizzard is fairly straight-forward when it comes to those.
Ask your friends to help ou questboost you. Also, join some sort of social lvling guild, that did help me alot.
Now i am in a 25 HC 24/7 raiding guild...
I'm on a page about incorrect corrections, and spent the better part of like two hours trying to get someone to understand that -5^2 = -25, not 25, and then that post had comments get reposted because that group is self sustaining, and that person was in turn trying to explain what I just explained to them. And I'm taking that as a victory
I will be AFK for a couple of days you guys hold down the fort while I am gone. I will be checking in on my phone but that will severly limit me. Be back saturday!