Professions skills are split between expansions now, you'll have a separate skill bar for each expansion. This means you can level the new Battle for Azeroth skill tier without putting any point into any of the previous expansions tiers, you don't have to level Leatherworking with older materials to be able to craft the new BfA items. You can read more about this in my BfA Profession overview.
How much effort are you willing to put in? The days of clicking the mission table and collecting a big pile of gold a few hours later are behind us. Our gold-making options for this expansion are pretty much just farming (materials or rare drops), flipping, and professions. All of those things are a time investment. If you're not willing to do any of those things, you're probably not going to increase your income.
Allied races aren’t much better. You can only earn them by grinding out reputation. It doesn’t take that long but casual players will need to invest a couple weeks primarily to it, and focusing on that grind will take you away from others, like earning gear. Each race has its own grind, but the things you do to work through it remain the same, adding to your boredom.
"Essentially the Scrap-o-Matic 1000 (and Shred-Master Mk1) works like the Obliterum Forge in Legion however one major difference from Legion is that you can use it to break down any gear obtained that is from the Battle for Azeroth expansion, including dungeon/raid drops, quest rewards, world drops and crafted gear. Apart from a chance at getting Expulsion you will also get ore, gems, leather, occasional enchanting mats (from scrapping cloth gear) and other crafting mats. The best way to obtain Expulsion seems to be from breaking down rare/epic gear you obtain from dungeons and raids, killing rare elites and doing world quests, it also drops rarely from BFA uncommon quality items."
With the most in-demand decks going for up to 20,000 Gold each, Basil believes that Darkmoon cards (12 of which when combined form a full deck) can earn scribes the highest possible WoW Gold. But he said that it takes intricate planning and logistics to really ramp up the Gold income from Darkmoon cards due to the constraints surrounding its crafting cooldown.
-Island Expeditions- Island expeditions was one of the new features I was looking forward to but Blizzard no longer makes games that are ready when they are ready but rather makes games ready when the deadline comes. Thus, many of the new features are completely stripped down from what was expected and it's literally just a small scenario you enter with two other players to continue to grind out your Azerite neck piece.
Patience and extra gold are rather important for the mounts so it might not be best for you right now. As for the operation (Wrath and Pandaria mounts right now), you need a miner (ore is cheaper than bars), transmutation master alchemists (living steel and some time eternals for daily cooldown, titanium and riddle of steel), and potentially multiple engineers (for more Sky Golems, plus at least one gnomish and one goblin if you want to do both rockets). The best way to source Pandaria mats cheaply is to buy up Spirit of Harmony when it's cheap and check often for mats cheaper than the conversion rate (1 Spirit buys 20 ghost iron ore, 5 trillium ore, 20 Kyparite, and more). Same with Eternals (for crafting titansteel)...you have to regularly check and grab them up whenever they're cheap (frozen orbs can be exchanged for eternals in old Dalaran too so watch for some cheap orbs as well). I also sell Golden Lotus on the side since it goes for more than the Spirit cost. (Edit: Also should point out that at the end of the expansion everyone is bored with nothing better to do so the profits on the mounts have dipped to as low as 5k.)
Mythic+ rewards will also go up by 30 item levels; however, during the first week of Season 2, rewards from end-of-run chests will be capped at Mythic 6 quality (item level 385), and the chest you open next week will contain Season 1 rewards if you do a Mythic+ run this week. (So, for example, if you do a Mythic 10 during the final week of Season 1, you’ll get a Season 1 item level 380 piece and 60 Residuum from your first Season 2 chest.)