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.
As part of Battle for Azeroth, players will be able to unlock new "Allied Races" to join the Horde and the Alliance, becoming playable after meeting certain conditions. Some of the new races are already available in the game for pre-purchases, while others will become unlocked while playing through the new content. Blizzard has also confirmed that beyond the ones we know so far, further races are planned to join the Horde and Alliance in future patches for free. The new races we know about so far are as follows.
You should equip new quest rewards when their item level starts beating out your previous set of gear. If you are currently wearing Tier 21 gear, it is best to let the quest rewards significantly beat your existing item level before using them. While a Tier bonus is worth a fair chunk of damage, the stats will quickly fall behind. Azerite gear additionally is another 1-3% per bonus, on top of raw stats.
Sometimes you can make money by crafting items with ingredients supplied by other players who give you a tip to make the item. This is not necessarily a reliable source at low levels, but it can be a good supplemental income source at higher levels, particularly if you have good recipes. And if you can charge for the customer using your materials (as opposed to materials supplied by him/her), you can mark those up.
The NPC scan and NPC alert method is an awesome way to build a stock of rare BOE items simply because you don't really have to try.  By installing NPC scan and NPC alerts, you can literally just fly over anywhere and be alerted when you pass a rare spawn.  As we all know, rare spawn loot tends to have higher item vales, as not everyone is able to consistently farm them.  Some NPC's, especially those in outlands have those higher item values when compared to the rest of the world.  As a goldmaking method I just everyone should be doing this.  It only requires you download two addons and you can get access to important NPC,s that you would otherwise never knew existed.  The opportunities are endless, I would generally never play without these cool addons.  Realy cool.
Once you get to about 200g, the theoretical limit of your profit virtually disappears. You now have enough money to start mass buying and reselling those players' goods who undercut everything by an extreme amount. Enchant mats are still a very good focus during this period, especially essences and crystals. You can now afford to buy several maelstrom and abyss crystals and wait until prices fluctuate to resell for a profit. A major strategy you can begin to employ is the multi-character trading and auctioning. If you come across 5 abyss crystals, get onto one character during peak hours and advertise a price 25-50% higher than average. When no one responds to this, quickly switch to another toon and offer the same 5 crystals for 10% lower than before. This will help to raise the median price because other sellers see what they may be able to get for their good. While they are cancelling and reposting, take this time to undercut their new prices, which is now more than you ever could have gotten before when prices were low. If you master this with BoE epics or more rare items, then you can make differences of thousands of gold.
This is an infinte farming spot that takes place just east of maraudon.   It requires you to stand in a specific spot which will allow you to kill all the slitherblade naga that surround the river.  This spot is generally a GREAT spot since the mobs respawn instantly after death.  You will get an obscene amount of silk, wool, greens, and low level patterns.  It's one of the only remaining infinite respawn farms left in the game.
An important aspect when selling transmog on the AH is that it often takes some time to sell. Therefore you will make more gold the more diverse your portfolio of items is. If you only farm one tier of gear. Lets say for example gear in the 60-80 bracket. You will be limiting yourself as the demand won’t be there and you will end up with too many items. You will end up with many of the same items for things that aren’t in demand but might sell occasionally.This means that spreading out your farming across all tiers is best, as you will get fewer of each item but more different items to meet the actual demand.
The entire Jade Forst is our farming spot for this one.  Literally, the entire Jade Forest.  The Jade Forest is crawling with porqupines and if you have a mage character, each one of them has chance to drop the polymorph porqupine tome.  Which is excellent, because these tomes have a selling point of 13,000g across the board. They are really easy to get, and noone really pays attention to these spots.  Try it if you like, I was able to get 2 on video, and have already sold one of them.   

This spot actually kicks BOOTAY.  And I only say that because it's so hidden, unique and quirky that I had to add it to this list, despite it being a method rather than a farm.  Generally what you want to do is some sneaky arbitrage.  We'll be buying the items Royal olive, Dalapeno Pepper, River onion, and Muskenbutter from the vendor for 2g – and reselling them to the AH for 4g+. This is an awesome way to take advantage of players laziness and the demanding reagent requirements for some of the higher end recipes.  By selling from the vendor to AH, you can make easy gold – in fact I suspect most cooks do not know these reagents can be purchased from NPC's.
Combat is turn-based and there is no time limit on each round in a PVE Pet Battle. You can take your time to determine which spell to use next. Some pet abilities have multiple round cooldowns, while others can do extra damage if certain conditions are met. Be creative and have fun testing which combination of attacks works best against different wild pets!
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.

Good question. Me personally, when I use a new strat from somebody else, I always read thru the strat, and in the case I really need to level some pet, I then (likely) exclude strats that are mentioning things like “RNG”, “risk”, etc. But: I’m always happy (when using a new strat) when I see some detailed infos, so that I can estimate what is going to happen. But YMMV.