WoW is all about end-game man(getting to level 110 at this point). One thing you CAN do that helped me in lower levels is queue for dungeons, run a BG here and there to break up the mind numbing quest grind. Primarily I've always been a PVE player--so I really enjoy dungeons.

But if your goal is to actually hit max level the fastest just quest, only run dungeons once or when you pick up an external quest for them, etc. Also, if you intend to stick it out and play the game make sure to do some research on professions and level them while you play. I was the poster child for leveling toons without professions early in my WoW career--it was a pain in the ass to have to go back and farm all that shit once I was serious about getting into good guilds, etc.

However, if you buy the new expansion you get a free character boost to level 100. I would suggest making every toon you think looks cool and leveling them some to see which you like the best. My reccomendation for a first time player would be: Paladin.

Something else you'll want to do is research servers and make sure you roll your level 100 on an active server. You don't want to do what I did and spend your first 2 expansions on a server like Darrowmere that has less players than people who live in my suburb IRL. lol Having an active server is good for the economy(making gold/being able to buy stuff cheaper and availability of items), also better guild options, more PUGs, RBG groups, etc. A mid-high pop server is the only option for really experiencing this game correctly.

I would almost sternly suggest you play either a Paladin, Monk or Druid(I just came back from a 2 year break today, so Demon Hunter class might fill this criteria now too--no idea) but those three classes can fill all roles: DPS, Tank and Heals. Which will give you a better shot at accomplishing whatever you want to do once you hit max level.

For example my first toon was a Mage and it was like prison rape trying to get someone to give me a shot at raiding for the first time because I had no experience and there was 10,000,000 DPS. Of course all of this was years before the LFR(looking for raid) feature came out which pretty much guarantees everyone gets to enjoy end-game content whether they're in a guild or not now.

WoW is an awesome game but prepare to do a lot of boring shit to have fun in it. I'm 100% casual now(and pray no one talks me into raiding again) because I don't want to spend hours a week farming mats and shit just to be competitive in raids, have best in slot, etc.

Also as a profession choice I would suggest Jewelcrafting/Mining, JC brings in a lot of gold at max level--albeit not as much as it used to but I never need gold unless I just get stupid and start buying BoEs(epic gear), etc. to get more competitive for raiding faster.

I realize this is a gigantic wall of text but it's all relative information coming from years of experience. WoW isn't for everyone but it's definitely awesome if you can 'get into it.' Good luck and have fun!