Valid pieces for Azerite empowerment are available for the chest, shoulder, and head slots of all classes. This equipment has multiple tiers of that can be unlocked, represented by a series of concentric wheels with icons representing individual powers; as individual powers are selected, they rotate into slots at the top of the interface, activating the selected benefit and locking out the others unless the player pays to reset their decision. Outer rings offer multiple choices, some based around the character's class and specification, others around the zone or circumstances in which the gear was acquired. The innermost circle offers no such options, instead being a boost to the level of the item itself, and thus providing a flat all-around benefit.
They seem to have expected some things, though, see adding pets with aquatic damage (gun and ooze) aswell as a resistant cockroach to stop us from cheesing everything with elementals. Yet, a fact their damage output is low combined with shields not checking for racial damage means this mechanic prevents a lot as you mentioned. The last boss has got an ability to remove basic shields so perhaps that was not in oblivion either… unlike the reactive damage. Also, an ability that forces swap altogether with an ability which prevents from being swapped, including critters? I can't say I like it.
You should equip new quest rewards when their item level starts beating out your previous set of gear. For healing, 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. With that said, you will unlock Azerite pieces early on, which can be worth using over Tier gear.
Battle Standard of Coordination: This item gives you 15% bonus XP if you stay within 100 yards, with a 10-minute cooldown. Can be useful if you are grinding in an area or when completing a dungeon. If you plant the banner at the last boss of a random dungeon you will get 15% extra from the bonus XP as well as that XP is awarded when killing the last boss. You need to be friendly with your guild to get this. The easiest way to get it on a new alt, is to buy a Renowned Guild Tabard with you main and send it to your new alt. Now you need to join a guild with the “A Daily Routine” achievement completed. So open the guild finder, if you’re not already part of a guild, and look for a guild with a lot of members since they are more likely to have the achievement, and ask to join. Then buy the Battle Standard of Coordination.
If you can answer all of those questions with yes, then you are in a position to make a lot of gold! You can continue doing every step to get to the gold cap as quickly as possible. The security achieved through this can buy you virtually anything you desire in the game, including achievements that would otherwise be impossible on your own, which leads us to the final gold making tip - Selling achievements. If you are the leader or officer in a guild, you can take good acquaintances on your raids with you for achievements like finishing ICC or any other hard raid achievements that your guild finds easy and manageable. I have seen achievements go for 20k+ if you find the right client! This is very situational, however, and is by no means necessary to hit the gold cap, it just helps!
Bags: This SHOULD be a no-brainer. The cheap-o version are Netherweave bags, but if you have the gold I recommend you get the largest bags you can afford, since it means you won't have to stop to clean them out as often. In fact, if you have an excess of gold, it's probably not even worth your time to stop and loot mobs that aren't quest objectives. This seems like a small thing, but over the course of 100+ levels, all those clicks to loot add up.
While leveling, try to make use of the new Battle of Azeroth experience gem, Insightful Rubellite, which gives you +5% experience. Equipping one of these requires a socket in your gear, so try to hold on to a piece of Legion gear with a socket or acquire one of the Legion Legendary rings since every class has one. Each of the rings includes a socket. You can acquire one of these rings rather easily by doing World Quests in Legion zones and acquiring 1,000 Wakening Essences that can be used to purchase a legendary ring in the Legion version of Dalaran.
The most simple thing is TradeSkillMaster. This AddOn shows you quite an amount of information in the items tooltip. In my opinion, DBRegionMarketAvg the best source. It tells me the price, an item was posted on all EU realms in the last 14 days. Why not DBMarket? DBMarket only shows you the items value from your server in the last 14 days. This value often gets manipulated. Some people start to post an item with a 500g value for 500.000 Gold on the auction house for several weaks. As a consequence, DBMarket is rising towards 500.000 Gold. If you use DBMarket with 100% and post your item for 500.000 Gold, nobody will buy it.