Raids open on September 20. Once you reach Level 110 what becomes to matter is gear! To ensure a step-by-step gearing up to be prepared for raiding and earning your raid spot, I've crafted this guide based on my own gearing up experience in Legion.
The Spec You Play!
The specialization you play matters! Currently, when you're a DPS trying to obtain gear from Normal difficulty dungeons, you're going to wait a lot. Queue times are anywhere between 45 - 60 minutes. So that's roughly an item every hour. Once you reach item level 810 queues are going to get a lot better; for DPS they drop to 8 - 10 minutes for Heroic dungeons. If you happen to play a Healer or a Tank, you're going to gear up insanely fast via dungeons, because you get instant queues. You just queue up for a dungeon picking a said role and instantly you get a queue pop up. So tl;dr: play a healer or tank to speed up gearing up.
Before delving deeper into Legion gearing, it's important to say that all Legion items can come with a +10 item levels added to their base, these are called Warforged. Sometimes items have a small chance to have up to +15 item levels, these are called Titanforged. Same thing goes for drops in dungeons and raids in all difficulties. Currently, the highest item level is 850, it will be raised to 895 later.
There are no weapon drops in Legion and relics are the only way to empower your weapon. Mythic relics empower your weapon item level by up to 40 item levels per relic. You can have a maximum of 3 relics up at the same time. Upgrading a relic will destroy the currently equipped relic. Weapons start at item level 750, so if you have two relics that add +25 item levels each, the total item level of your weapon will be 800 (750 base + 50 item levels - the upgrade).
Questing remains your main source of gear throughout leveling. The most relevant items are of an item level 800 and you will get them by completing the Pillar of Eternity quests.
Normal difficulty dungeons drop 805 item level, Heroics 825 and Mythic start at an item level of 840. Note that all gear has a chance to be Warforged or Titanforged.
World quests are unlocked upon reaching Level 110 and reaching Friendly with all Legion factions. You'll have to venture to Suramar and quickly reach Friendly as this is the only reputation you will be missing when heading to Khadgar at 110. The item level rewards vary and depend on your current item level to be relevant. The rewards start at 805 item level. The better your base, the better rewards are offered. So the total item levels you can get vary from 805 - 850. World Quests appear on your map once unlocked. They are scattered across Broken Isles and once you complete all (similarly to a Diablo III bounty, you receive a bag that has a chance to contain additional, even legendary loot.
There are no equip limitations to crafted gear in Legion. If you have the gold, you can be fully equipped in crafted gear. The gear starts at item level 805 and can be fully upgraded up to an item level of 850. With an item called Obliterum, you can upgrade a crafted item by +5 item levels.
Order Hall Set
Completing various goals in your Order Hall will get you an entire set. This is an eight-item set and all of the "achievements" to get the different slots can be completed solo. The gear ranges from 810 to 850. You get the Helm straight away. It is of item level 810 and can be upgraded to 840 for Order Resources except for the Shoulders. To unlock various slots, you will have to obtain 100,000 Artifact Power, reach Exalted with Nightfall, reach Revered with 2 Legion reps, complete your class order campaign and much more.
Legion Reputation Items
All Legion reputations come with an item level 820 item at Revered and a 850 piece at Exalted while the Nightfallen have 800 item level boots at Friendly and a 840 item level necklace at Revered.
Legion comes with Legendary items that totally alter your play style to make use of the new Legendary. At the start of Legion there's a limit of having only one Legendary item equipped. Legs are of an item level 895 and are random world drops. You can see them drop virtually anywhere. The developers commented that the chance to receive Legendary loot if you have not yet received any will increase with time. After working on Order Advancement for 43 days, you will unlock the ability to equip two Legendaries.
My Gearing Up
I'm playing a Restoration Shaman, meaning I take full advantage of the short queues. I was able to level up my character for Heroics in a matter of hours. Now I'm farming the hell out of Heroic dungeons to grab lots of Titanforged items and I'm adding World Quests to fill in the gap.
All the aforementioned ways are the possible means to obtain gear prior to raids. Hopefully this guide has brought you some insight.