1. Don't just take anybody with some gold willing to go. Make sure they at least have some heroic gear or better. Bringing someone in greens not only hurts your chances of killing the bosses, but these players often anger those who are in better gear that need one item and then get outbid by some "noob". You are looking again to establish relationships and repeat customers!
While not as powerful as it was before 7.3, this transmog spot is a good area to amass a large number of BOE greens that generally fly around the 35 – 42 area.  It's popularity stemming from the amount of items that drop (and the potential value of those items) rather than the quality of each drop itself. Generally drops from these farms can take a while to sell even when using my TSM posting style.  However if your low on transmog stock this can be an awesome area to hit every now and then.
If you already have a high-level character and want to quickly level up a new one, by far the best tools for the job are the items labeled “heirloom gear.” These pieces of gear have two very special properties — they bind to your account, so any character you own can use them, and they grant bonus experience. Their stats also scale with your character’s level up to a certain point, so you can equip a fresh character with heirloom gear and power through much of the game.

Nearly all quests offer cash or items as a reward, and often both. While completing quests shouldn't be your main form of wealth generation, it is something you are going to do anyway. The key to making the most of quests is picking your reward items wisely. Don't always pick the item that most fits your class - if it isn't demonstrably better than your current item, instead go for whatever reward sells for the greatest amount to the vendor. You can select the in-game interface option to display it in the tooltip. In general, if you can't use a quest reward for your character, pick either a plate-armor or melee weapon as your reward--these tend to sell to vendors for more than other items.

TSM has a very steep learning curve, as it is a total profession framework. It does not hold your hand, and requires a lot of setup. Luckily you can import settings from other players and there are a ton of settings out there. I have published most of my settings in my pastebin here. You can also check out Sheyrahs. If you want to learn it from the ground up I suggest one of the following guides: PhatLewts, Sheyrah, WTBGold.

Once you're level 32 or 33 head back north through the Stonetalon Mountains to Desolace. You will need to go all the way to the South West portion of the zone to get the Horde flightpath you will be able to pick up quest at Kodo Graveyard outpost on your way to the Shadowprey Village Horde area. Do all the quests you can find in those two Horde areas and make sure you are level 36 before we head out to the next zone.
Vol’Dun is the hardest and most tedious of the Horde Zones in Battle for Azeroth. It’s also probably the one that makes the most sense. Each sections of quests leads directly to the one you should do next. For all of these reasons it’s going to be best to get this one done early. Thanks to any legendary items you might have collected in Legion, you’ll be strongest in the leveling process before 115 and weaker after — because that’s when the legendary effects stop working.
5. at least get 4 characters with these professions. Tailoring/Enchanter; Minning/jewelcrating; Minning/Blacksmithing and Herbalist/alchemist. You can skip blacksmithing and take Minning/herbalist with 1 of your alts. While doing your world quest in argus, try to get all the ores and herbs that you can. Send all the cloth and greens to your tailor character.
There is a constant market for transmutations. If you are capable of doing these, you can charge an upcharge on each of those transmutes. A player who logs on his/her character each day, and sticks to it, can generate a significant subsidiary revenue scheme through transmutes. Likewise, if you have a transmute that allows you to transmute a lower value element (such as Earth) into a high-priced one (like Water or Fire), you can make a cool 15-20 profit every day by simply doing your transmutes.
A farm that I myself made drastically popular about 2 years ago.  This farm is a simple pet and transmog spot that requires you to pull the entire wailing carverns instance.  Besides how it sounds, this farm is VERY easy going and can literally be done while you watch something else entirely.  (netflix maybe?)  While it's not as potent as it used to be, it still has some merit in it, especially if your server is low on the deviate hatchling pet.  While it does take some time to drop, I can usually average  a deviate hatchling every 30 minutes or so.  However, since I released the video on it, the price of the pet has dropped wildly.

If i start on a new realms, I am farming a lot of transmog from classic and Burning Crusade Dungeons and Raids. In the beginning, i start to post them if they have at least a DBRegionMarketAvg (Average value of an item on all EU realms of the last 14 days) of 500 Gold. All the other items get vendored. The time you hit a stock of 1000 Items, my value treshold raises to around 2.500 Gold. All the items below that value get vendored aswell. Newly farmed items that are above these treshold will be listed. Why? If I start over somewhere, I want to get a certain amount of gold quickly. Cheap items are great for that. Later on, to save time, Quality is better than quantity. As mentioned above, re-posting the items on the auction house takes quite a bit of time. At this point, I can recommend you the TradeSkillMaster AddOn, it makes your auction house work really a hell of a lot easier.