Isle of Quel'Danas: Special mention. At lvl 70 you can start doing the dailies here. Despite not being able to fly, the quest density is VERY high. I recommend hitting this every reset if you spend more than 24 hours REAL time(not /played)in the 70-80 level range. In fact, if you're doing a monk and only logging in once each day anyway, IQD WILL be your best exp/h for this level range.
Azerite equipment is currently balanced around being able to unlock the outermost, earliest tier of power immediately upon acquisition, while delaying further advancement until the Heart has been further empowered. For example, the first piece of Azerite equipment, gained shortly after the Heart itself, is fully empowered once the Heart of Azeroth has reached level 3. A character at 120 (the maximum for the expansion) may find a piece whose first tier requires the Heart to have grown to level 12 or greater.
Anyway, however you choose to get to the addon's menu, choose guide list and then pick the zone you want to quest in. There are some zones that will autoselect based on quests in your log, but not all guides or all quests are set up that way. (If you don't want to switch to a guide that auto-pops up choose "not now" or "never") As you can see in the screenshot, there are various categories of guides. Most max level content (such as Argus) is found in Achievements rather than leveling.
For Alliance it's Lok'Modan, Redridge, Darkshore, Felwood, Stranglethorn (both parts), Plaguelands. Somewhere between 3 - 3.5 of these get you to 60 in like a 16 hours /played, if you queue for dungeons at the same time. I recommend dropping everything at 45 and going to Darkshore-Felwood if you didn't do them yet - they are literally the fastest levelling zones in the game right now, maybe only trumped by Silverpine.
Rogues can make fast money from pickpocketing mobs, opening lockboxes and selling items that drop from those on the AH. If you don't have a rogue make one and get him to at least level 16. Rogues can also make some money by picking locks for people and getting tips. Not a great revenue source, but a decent one to supplement multiple strategies for making money. Generally, the usual lockpicking tip is between 50s to 1 gold, the most common being 50 silver. Sometimes, you can get lucky and have someone tip up to 5 gold for lockpicking several (or even just one) boxes. It's always beneficial for a rogue spending time doing repairing, training, etc. in a city to put up a lockpicking advertisement on the trade channel. Just make sure you let the buyers decide the price and that your lockpicking level is high enough.
First of all, the value of transmog is decided by rarity and how they look. Some items like Minenarbeithut der Tiefen or Pendel der Verdammnis (they can drop in Uldaman) are worth millions of gold. They are worth so much, because they have a really small chance to drop. Other items are bought well because they look good. Best example in this case is the Glorious set, its legplates Glorreichen Beinplatte reach a 100.000 Gold value easily.