I mean, You cant really 'outplay' a garen. All you have to do is play off your early lead, because if you lose this matchup early, you're pretty doomed. I like all in'ing garens because they just go for the q/e level 2 and start aggroing you early on. This is where you keep autoing level 1 to keep stacks and kill the 7th minion (first of the 2nd wave) to get the 5th stack and level up E instantly to all in him. Since the wave will be frozen, he has to walk up, you e him, q him once, pop a corrupting, get that sweet time warp move speed, and just walk next to him and auto, once he flashes, if he's low enough, you q again. If not, well now he's flashless, you'll get him next time :3