Leveling Guide (Heroic)
UPDATE June 25, 2020: Noobicabra on YouTube created a Level 1 to 20 in 14 hours speedrun guide playlist with 162 videos quest by quest including repeats on certain difficulties and good XP quests. Some techniques for new accounts are not possible due to his usage of bank items but it is still a good benchmark for leveling as you play the game more.
https://www.youtube.com/playlist?list=PLGM3BpP6RIAdvxjpRakR9-lS1aJZunuNC
For older or outdated leveling guides see below or https://ddobuildmasters.com/2018/01/24/post-reaper-tr-path/
First after exiting the Grotto, talk to Valeria at Korthos Village Pier and skip to harbor. Go to the west side of harbor, find the green anchor icon airship portal. Enter airship, click on amenity bar antenna to get guild airship buffs (including 4%/5% XP boost).
(Note this guide recommends doing quests on elite first for the Bravery bonus)
Level 1
Do Information is Key once on Elite, once on Hard, then three times on Normal, do Bringing the Light once on Elite, Hard, and Normal
Level 2
Do Kobolds New Ringleader once on Elite, once on Hard, then five times on Normal.
Level 3
Do the Waterworks chain on Elite, do Garrison's Missing Pack, Durks Got a Secret, Haverdasher, Walk the Butchers Path, the Sunken Sewer, and Missing in Action quests on elite
Level 4
Do the depths chain on Elite, Hard, and Normal, do the Shan-To-Kor, Sharn Syndicate, and Catacombs chains on elite.
Level 5
Do the Necropolis 1 chain on elite, window-farm the bloody crypt until you hit level 6
Level 6
Do the Tangleroot chain on Elite
Level 7
Do the Delera's chain on Elite, Hard, and Normal, window farm parts 2 and 4.
Level 8
Do the House Kundarak Quests on Elite to get your bank upgrades, do Tharashk Arena and the Prison of the Mind on Elite
Level 9
Do the Tear of Dhakaan on Elite, do the first four quests of the Necropolis 2 chain on elite
Level 10
Do the Shadow Crypt on Elite several times
Level 11
Do the Jungle of Khyber quest on Elite several times
Level 12
Do Tempest's Spine on Elite if you find a group, do all Sands walkup quests on elite, do lordsmarch chain on elite.
Level 13
Do Sands flagging quests on elite, repeat Chamber of Raiyum several times on hard or normal, do the first four Necropolis 3 quests on Elite
Level 14
Farm the Cursed Crypt (Necrpolis 3) on Elite, do the second Lordsmarch Chain on Elite.
Level 15
Do Gianthold walkups on elite, repeat them on hard or normal. Do Lords of Dust chain and Disciples of Shar chain on Elite. Repeat them on hard and normal.
Level 16
Farm the three flagging quests in Gianthold on Elite. Do Gianthold Tor on Elite, Do Necropolis 4 quests on Elite and repeat them on hard or normal
Level 17
Do the Harbinger of Madness Chain on Elite and repeat it on hard. Do Litany of the Dead on Elite and repeat it.
Level 18
Do all the Vale Quests on Elite then repeat them on hard and normal, do monastery of the scorpion on elite and repeat it several times on hard or normal.
Level 19
Do Inspired Quarter 1 and 2 on Elite and repeat them on hard and normal. Do some of the Amrath quests on normal, hard, or elite. Do the Reign of Madness Chain on Elite.
Level 20
You've reached Level 20! Congratulations! Now you get to farm epic dungeon and raid tokens, true reincarnate, and start all over at level 1. Hooray! :)
Leveling Guide (Epic)
Epic leveling can be a bit harder than heroic leveling. It might be preferable to find a group. However, it is still very possible to solo quests in epic. If you are concerned about losing bravery bonuses, then use the bravery marshal on the airship to pause your streak.
Levels 20 to 28. Repeat all these epic quests twice a day on epic normal (do higher difficulties if you are comfortable with them or have a good group)
Jungle of Khyber, GH Quests (Foundation of Discord, A Cry for Help, Prison of the Planes, A Cabal for One, Feast or Famine, Maze of Madness, Trial by Fire, Madstone Crater) Offering of Blood Chamber of Raiyum, Lord of Dust Servants of Overlord, Spinner of Shadows, Beyond the Rift, Spies in the House, Desecrated Temple of Vol, Inferno of the Damned, Fleshmaker's Laboratory, Ghosts of Perdition, Ghost of a Chance, Legend of Two-Toed Tobias, Garl's Tomb, and Devil's Assault.
Feel free to venture out and do other epic quests in Eberron, Eveningstar/Wheloon if the tedium of repeating the above quests bores you.
Tips for Fast XP
Best Quests for Fast Experience Points
1) The Shadow Crypt
2) The Jungle of Khyber
3) Litany of the Dead
4) The Kobold's New Ringleader
5) The Chamber of Raiyum
6) Desecrated Temple of Vol
7) The Tear of Dhakaan
8) Spies in the House (Epic)
9) The Bloody Crypt
10) Gianthold walkups and more!
for free to play accounts check out