New to WoW: A few basic tips

I'm still relatively new to World of Warcraft. I've been playing for about 3 months, but only on and off with a few days here and there of serious questing. The highest ranked character I have is a level 15 Tauren Warrior. In any case, I'm at that intermediate stage where I'm starting to learn a lot of things that the seasoned gamer takes for granted and that the complete newbie has no idea about, so I thought I'd share a few of these basics that I've noticed recently for those of you who are just getting started. These will most likely garner "Well, d'uh" from those of you who have played the game for any amount of time. In any case, here's three random bits:

Yesterday, when I was riding over to Mulgore, someone else on the airship with me kept asking "Where is this going?" I then told him/her to hit M to pull up the Map. n00b: "Oooooh!"

Also, while at the Crossroads when you see the little guy with the big guy as his bodyguard on the road selling weapons, if you think, "Wow, that seems a bit overpriced," that's because it is. Don't buy from him.

You can kill as many Plainstriders as you want, but if they are not in the area that the quest you are on says they need to be when you kill them, then you're not going to make any progress on that quest.

Any other tips that you'd like to share?