I've already played a number of hours since installing the game (and being extremely pleased that my 3-year-old computer and video card could run the game), and my current primary character Valdesta is coming up to level 10 shortly.
I haven't found out what Realm my nephew is in, however, so it's very likely I'll be abandoning this character, or using it as a secondary one very soon in the future, which is why I write about as my "current" primary.
Some Things I've Already Learned
I've learned how to hunt with my bow, I've received extra training so my ranged skill is even more deadly, and I've upgraded my axe for the inevitable hand-to-hand combat of solo playing.
I have figured out how to swim not only through water, but underwater, and to my surprise I'm able to use my ranging equipment and skills underwater with limited problems! Sometimes it looks like I should need ground beneath my feet for leverage to stay in place, but nope!
I've learned that running through a cave full of monsters - even small ones you can handle no problem one-on-0ne - can be deadly and thus is unadvised. I now make sure I have enough arrows to get me back out if I go super-deep into a dungeon, and I do it the patient way.
I've learned that death isn't all that bad on World of Warcraft. You don't drop anything (including coins) that other players could pick up/steal from you before you get back to your corpse to recover it, after all. You DO suffer a reduction of equipment quality each time you die, but it's relatively cheap for a low-level like me to repair my equipment back to "full quality" status once I found a weapons and armor trader.
I've learned that fighting in a party is WAY easier than fighting alone, but that it takes different co-ordination than I'm used to from the text-based MUD games I've played for years as my primary RPG's.
I've learned also that quests can also be called "trainers", at least at the low levels. I've been pleased at the rate of challenges coming towards me through the quests themselves - some challenges are physical, in that foes are higher level and more deadly than in previous quests... some challenges are technical, in helping me figure out how to interact with the World of Warcraft environment in every way possible.
I'm sure I've learned a lot more, too, but I think it's time to end this post!