Sorry about the salt but jeez, stop listening to guides. Just check your AH, see what old mats are low in offer, and go get em. >FOR EXAMPLE<, ghost iron ore is a gold mine right now, cause nobody can sustain the demand, and prices are way up. Plus side being, old farms are optimized like hell. You can fly in the old world, mobs won't bother you, no one is there to take your nodes, and there are plenty of items to make the most out of it. Which means it's way easier and requires less effort than farming in BfA.

That's mostly it, but it's linked to the fact you can transmute ghost iron bars into trillium bars, which can be transmuted into Living Steel. So ghost iron is really really useful for sky golems and panther mounts, because they require 4 Living Steel's, which means 24 trilliums or 240 Ghost Iron bars, if you wanna go that way instead of farming the trillium itself!

A new expansion unlocks exponentially more powerful gear, letting you easily breeze through Warlords of Draenor dungeons and raids. A great gold making strategy is to solo these challenges and amass a large amount of gold that you get to keep instead of splitting with your group. Start with soloing easy dungeons and work your way towards harder dungeons until you are comfortable enough to take on soloing raids. Speed and clearing ability is key – stick to those you can run through without skipping a beat and you will see your gold making per hour go through the roof.
The best way to collect AP is through world quests, a system that allows players to complete menial tasks to earn moderate rewards. A finite amount of AP spawns on the map through these quests — generally at least 2,000 a day. I’ve likely done most of these quests close to 20 times in the course of preparing my various characters in the 45 days since the expansion launched. In some cases, I’ve replayed them as many as 50 times.
Don't have data from beta and didn't read much into this, so i just speculate based on what i've seen, that there are different champion equipment craftable, each with different bonus. So my guess is that people will use these equipments pretty much similarly as they use glyphs (from a market analogy): equip their champions once and be done with it.
In a few months only mats will be worth anything. At this point we have people with tens of millions of gold and people with just a few thousands. A flask takes tons of mats to make, and they will sell for well over 10k gold each, so the casual players won't afford them. When people realize that the rich guys will always take buying from the AH over farming their own mats, the prices will go even higher, then casuals will notice how expensive flasks are, and they will pick up alchemy and make more flasks, driving the prices down again.
There's a few profession crafted pets in BfA on the horizon - Battle for Azeroth Tailoring is getting a Hot Air Balloon style pet, and BfA Alchemy looks to be getting a brand new Transmute Meat to Pet. There are some mount buff consumables from both BfA Leatherworking in the form of a mount barding, and Blacksmithing in Battle for Azeroth will be able to craft Stirrups and Hoofplates to increase mount speed and allow you to interact with things while mounted.