With Mining, from the moment you take the skill you can make good money selling stacks of the bars or ores in the Auction House. Blacksmiths, Engineers and Jewelcrafters are interested in the bars, while Jewelcrafters and even other miners may want to buy the ores. Make sure to check the relative prices of ore versus bars before smelting. As your skill increases, so does your earning potential. At the maximum level you may smelt Titansteel for a daily fee.
I am currently working full time on my Vanilla WoW leveling guides.  Soon there will be a 1-60 speed leveling guide for Alliance, along with in-game guide versions available for my members area.  As of right now, there is no members area, but if you would like to show support for my efforts into this project, you can simply donate to me via Patreon if you like (you will get some cool rewards in return).  Or you can donate directly with PayPal if you like.  All donations are highly appreciated and they will only motivate me more to continue making the best vanilla WoW leveling guides on the web.
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.
Only really to expand on Gráinne's comment as regards the 'collecting' and 'roster development' sections - which are, as said 'distinct' although they are intrinsically linked - I would like to point you in the direction of the in-game Achievements > Battle Pets > Collect tab. There are a series of achievements called Raiding With Leashes, pretty much all of which can be completed via the auction house - if you have the gold/inclination - or by completing old raids.
The goblins of the Steamweedle cartel have set up several neutral auction houses about Azeroth. Gadgetzan, Booty Bay, and Everlook all house neutral auction houses. The neutral is useful for making money, as commodities that Alliance players can get easily can be sold at a cheap price to Horde players (or vice versa), and then sold at a higher price at a major city.

Of course this is pure speculation, but who thought the token would be beneath 200.000 Gold again? But the only thing important for you is to calculate at what point you make profit by selling the tokens again. If you consider it, you should take the risk! Worst case scenario: You have a lot of battle.net balance to spend for Gametime, mounts, pets and boosts/services!

To exit a instance quickly. Create a group in the Group Finder when you are finished in the instance, then leave the group. You will then be ported out of the instance after a minute. When you got a dungeon down, you can make and leave the group around one minute before you reach the end of the dungeon and you won’t have to stand around and wait for 1 minute. This will teleport you to the nearest graveyard, on most dungeons this is right outside but on some there is a bit of a run.

Heirlooms can certainly be used with our guides! You may find yourself getting ahead of the guide. If you start doing gray quests, just skip ahead to a later zone. The guide is just that - a *GUIDE* not a rule, as many people seem to think. Feel free to skip parts! Watch out for quest chains, though, especially in the last part of the 50-60 section. Hopefully we'll have some awesome features in our new addon that will make it easier to skip around!
The Auction House (AH) is a brilliant way of making money if you know the tricks on how to do it. The basic strategy with the AH is to buy things cheap, re-list them on the AH, and then sell them for a profit. Even better, of course, is to get good items from drops and then sell them on the Auction House for pure profit. Many players generate most or all of their cashflow simply by speculating on the AH. So a good understanding of the it, as well as some time to invest, is essential to turning it into a money-making proposition for you. It is also highly recommended that you get the Auctioneer addon for quick listing auctions, and knowing the average price of items. Another great addon that can assist you in flipping items for profit on the Auction House is Tycoon. This addon analyzes items on the Auction House such as cloth, ore, and even TCG mounts. Once the information is recorded, Tycoon will inform you of the most profitable items possible, and exactly how much you can make by either farming them, or buying them at their current price and then relisting them.
Different qualities aren't limited only to wild pets—many rare World drops and special non-wild companions have had their stats boosted. For example, the world-drop dragon whelps (Azure Whelpling, Crimson Whelpling, Dark Whelpling, and Emerald Whelpling) are of [rare] quality. Check your Pet Journal to see the color-coded rarity of your non-wild pets.
The Mythic Dungeon International (MDI) is a global tournament where the top dungeon-running teams in the world use their skill, intelligence, and creativity to secure the best times possible in some of the most difficult Mythic Dungeons on offer. We are entering the first tournament of the year, the MDI Spring Season, so here’s a breakdown of what you need to know!
Once your character makes it to Outland and beyond, cashflow frees up considerably. The quest rewards are much better than in Azeroth. In fact, a typical character will earn from 1000-1200 in quest rewards and vendor trash while leveling 60-70 in Outland, and perhaps 1400-1600 from 70-80 in Northrend. The tendency is, therefore, to spend more freely after one hits 60. However, it is important for players not to go crazy on their spending once they make it to Hellfire. One thing is, training costs, repair costs, and consumable costs are also higher. More important, there is a large purchase that you are going to want to make at some point after level 60, your first flying mount and skill. The "bird" costs 40, the skill will cost you far more. Not only that, but if you want to fly it in Northrend at level 70, you'll have to shell out another 400 for Cold Weather Flying. And for those characters who will be 'farming' herbs or ore in either Outland or Northrend, an elite flying mount is almost essential, as it helps you gather almost twice as fast. That's another 5000 you'll be looking at. Therefore, budgeting carefully during the 60-80 leveling process is essential to ensuring you have sufficient cash on hand for making those purchases. Saving your pennies early makes that bird appear that much sooner.