I second that emoticon on WowWiki - it's pretty good, there are other guides out there but this is a good all-in-one-place-and-free thing :) One thing I had drilled into me - ALWAYS LOG OUT IN AN INN, or someplace where you're resting, like a major city. Rested XP is The Awesome :D

Also, the last time I played WoW was pre-cataclysm... So back then, it was mostly "Welcome to a field of snow, KILL ME SOME PIGGIES/WEIRD TROLL THINGS, none of which are aggro for a few levels".

(Also-also, from what I recall, many of the OMGMASSOFMOBS things were purely caused by someone getting too much aggro, then fleeing faster than the other folk around them).