There are more passive methods to gain wow classic gold, but these are slower. For example, many people choose to fish in places like Tanaris, or kill Harpies in Feralas and loot items such as mageweaves. These are rather AFK-able, but again, not as rewarding. Some people choose to favour fun over anything, and like in any MMO (massively multiplayer online game), the best way to have fun is playing games with friends or your guild. Dungeon runs with your friends provide social interaction and are definitely helpful over the long-term for your gold stack!
Mounts also take up space in your bags, bags which will of course be much smaller. Every bag space counts. With no guild banks, and much smaller storage space, your bank alts are going to be essential. You’ll need to remember to always post everything back to a bank alt, and to remember to get everything from the mail box to the Auction House. Which is only in Ironforge or Orgrimmar.
An advice for those who are trying to compete monopolizers: you cannot beat them by selling for less if they follow right steps. You should do opposite: sell for more. Because market will come down if the price goes unreasonably high. You can set a bid on item for the price it should cost and buy out price for higher than a monopolizer is selling. So, common buyer may get an item for the right price or monopolizer has to buy the item at his loss.
It is a great advantage to start making some silver and your first gold coin at low levels already. Skinning is a nice choice here. Fast and easy way to gather resources, leather of all kinds while leveling for those who are at the race to level 60. There are many good spots to grind beast mobs and skin them. I like doing it as a Troll Hunter, trolls have a passive racial ability: + 5% bonus damage against beasts.
...but, in my experiences, I found dual wielding to be fine. But only if you're Fury. I found that having two weapon swings meant having twice as many chances to crit, which led to lots more Flurry procs. At level 50 with two blue 1h swords, my kill speed was just about the same as when I used an epic 2h axe. And I wasn't even specced into the offhand damage talent. If I got a good string of crits, I could smack mobs down in 15-20 seconds, and easily hit Bloodthirst every time it came off CD.
Travel Time is what you will be doing the most of, thus talents or abilities that increase movement speed will likely have the highest impact on leveling speed.The more important concept is this: Shaving off seconds of downtime between pulls is equally valuable to shaving off seconds of In Combat Time. When you think about it this way, Damage Mitigation and Regenerative talents / abilities / stats have almost offensive properties and should potentially be valued equally to stats that increase damage.