One habit to change: Start every fight with at least one and a half Infuse charges.
Good into
JunoSnipe her with infused shots when she floats in the open, and answer her ult with yours.
EchoShoot her in the air; hitscan finds her wherever she flies, and she has little cover up there.
PharahTrack her with hitscan; a drone on yourself speeds your shots.
Watch out for
DoomfistLands on you from range and chains his cooldowns into a kill.
SojournOut-trades you at long range with a charged rail.
SombraEMP destroys your ult carrier outright; Weaken halves your damage and healing.
Best maps
Ilios on Control and Circuit Royal on Escort
Maps with high ground only flight can reach
Playing against Doctrine
His big frame and his ult carry the fight. Shoot him from range, cleanse or destroy the ult, and catch him with his dash spent.
The full guide is in the app
All 53 of Doctrine's matchups with a plan for each, map tips, comps, perks and kit. In a match, Hardstuck tells you when to stay on Doctrine and when to swap.