With Legion Remix live for a few weeks i figured out a way to level up very fast and also get strong fast. Below is the short version and an explanation below that.

Level 10 – 20

The first 10 levels you can’t do raids yet so you will first do Infinite Research quests, you can pick those up on the floating Island in Dalaran. When you complete a Infinite Research quest you get a ton of XP and a 1% xp gain increase on your whole account for remix. If you completed all of those you can do normal quests to get to level 20.

Level 20 – 80

At level 20 you can start doing the Emerald Nightmare Raid and Trail of Valor on LFR and Normal. I would advise to do them on normal because they are faster. By the time you have done those you will have unlocked the other raids too. You can pick up Infinite Research quests between raids and try to take on that you can complete in the raid. If you did all the raids you can go back to questing.

Level 80+

Once you get to level 80, you need to focus on gaining Infinite Power and Infinite Knowledge. Infinite Knowledge increased the amount of Infinite Power you gain from all sources. You get them from achievements like completing all main quests in a zone or complete a raid on Mythic.

While Raiding you get 2 important items apart from regular loot.

Fragmented Memento of Epoch Challenges

You need to collect 100 of those, when you have 100 you can use it and gain a lot of Infinite Power.

Mote of a Broken Time

When you have 10 of those you create an item, this item is always a few item levels higher then your average item level. So if for example you have item level 600, the item you get from the motes will be around 605.

Infinite Power

Why do you need Infinite Power? Well you need it to upgrade your artifact weapon, After the first few slots you need to choose a row, if you complete a row you get one last slot called Limits Unbound, you can use Limits Unbound 999 times, each time you get one Versatility. This will greatly empower your character to a point you can solo Mythic raids.