You will need initial funds to start this way. Buy for cheap and sell for actual price or higher – that sounds pretty easy. But you should have basic knowledge of prices and always track the market. People use to sell for cheap when they need fast gold or don’t know real value of the item. So, it’s your chance to act. If you see anyone selling an item for low price in trade channel, contact them immediately. You should use all of your trade skills to negotiate about the price to make it as low as possible. It’s important ability to communicate. Besides, it’s good to get addons to trade effectively on Auction House: Aux or Auctioneer. They allow you to scan auction, compare prices, find cheapest options, post items quickly, and many other useful tools. It is possible to make your first thousand out of ten gold you have in a pocket.
You can also make good gold for opening lockboxes, park yourself in a public place like Ironforge Commons or Orgrimmar near the Auction House, and let Trade Chat know you’re available. You can even make gold by offering to stealth in and pick the Shadowforge Lock open in Blackrock Depths! You’ll need to level up your lockpicking though, so work hard on it like any other profession. Try Redridge, Wetlands, and near the coastal nagas in Ashenvale.
Instead of sharding the zones, their plan is to shard the entire continent at launch. In Classic WoW, there are no dynamic spawns and questing in starting zones would quickly become annoying, so it's understandable that the game is all but fun when there are no mobs to kill, but layering will also cause you to see new players, every time you sign in to the game, which is a clear downside of the tech.
It is also worth noting that World of Warcraft Classic isn't exactly an archive from 2006. It has been rebuilt from patch 1.12, using modern data architecture and reaps the benefits of the modern engine. This means a lot of non-controversial quality-of-life features will still be present and it is possible to run WoW Classic servers on modern server architecture. As you can imagine, much has changed in the last 13 years in the tech space. That's before smartphones were even a thing. The modern engine no longer allows certain behaviours that could be used to get out of bounds, also adds widescreen monitor support and accessibility options! However, it does have the disadvantage of not being able to run on 32-bit systems which isn't that kind to older systems considering the game is from 2006.
However, after a while the novelty of it wears off and you do start getting a little bored of all the eating and drinking (and wondering why your character isn't getting to Kul Tiran levels of fat), especially if you hop on to BfA for a bit in between. The difference is huge and once you're used to just slamming into 5 mobs and downing them quickly it can get a bit boring to just pull 1 mob at a time and then wait and wait. The really low levels aren't that different between live and Classic in terms of gameplay however, as the small amount of abilities means combat isn't exactly the most exciting thing in either. On live you get past that pretty quickly, but it takes a while longer in Classic (especially if you're playing solo).
One may think that the AH may suffer a reduction of competitivity, leading to higher prices, but in an healthy server the gold farmer's farm will be taken over by actual players. Giving the chance to a more fair gameplay where you can go out and farm the materials that you need, instead to see them always farmed by gold sellers that sell them to you, without letting you many room to make gold in a fair way.
You won’t get extra cloth by farming cloth on your tailor, so you can bring any character. The most expensive cloth will be mooncloth, with a 4 day cooldown. Grab that pattern from Qia in Everlook, Winterspring. The second best cloth will be runecloth. That’s best farmed from the ogres in Dire Maul, Twilight mobs in Silithus, and the trolls in Zul’Masher, which is north of Lights Hope chapel.
If you like playing solo – there’s no better option than the Hunter. Hunter is considered the most efficient solo-leveling class so you’ll ding level 60 in no time. As a Hunter, you will be able to tame various beasts across the world and use them as your pets. Pets help you tank groups of mobs and enable you to tackle some of the group quests alone. However, their PvE power falls off in the end-game, but their PvP potential is enormous. Skilled Hunters are a pain to deal with since it’s almost impossible to catch a masterful hunter.
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.