Lmao, just played a game vs him a few days ago when i went top just for a change.
You don't, you simply don't.
His kit is based entirely to 1v1 people: his early game is protected by his hp sustain, so the only opening that's left is a gank or an early game lane bully.
His ult makes him unbeatable unless he hugely fucks up, as you will need probably 33% more hp than what you currently have at lv6 to kill him.
Tryndamere is basically what i call "a human zzrot", his only job is to run it down top™ and push waves and turrets ignoring everything else.
"But zelorxon, how do i win against him then?"
Rotations, as he doesn't have any rotations in his choices, your team needs to come and stop him before he snowballs on you, you have to group and fight/push an objective before he manages to push a turret on his own, he has 0 utility in a teamfight and outside 1v1s he sucks balls.
You need to roam and use tp around the map WITHOUT focusing on fighing him, you itemize for waveclear, you push and then you roam, once you'll have an advantage is then the time that you can actually try to 1v1 him, and he won't be able to do that, for the same reasons explained above.
Tryndamere is the ultimate plat and below nightmare, as he needs help from your team and knowledge about what rotations are, a knowledge that for the simple fact people are in the elo they're currently at don't own.
But if you can't manage to beat him in lane, just focus on reduce his impact on top lane, as other lanes and jungle will probably carry you without much effort.
The problem with bronze and why he's so oppressive there it's simply because people instead of knowing that lane phase ends at lv7-9 they manage to make it last until 20-25 minutes, which is deep mid game.
I end with the general tip true for every role, always and forever, after lv7: push.
Also this:
https://www.youtube.com/watch?v=43IlSomhiC4
he feels unstoppable. There is no strategy I've found to work around him as a melee champ. If I go in, he will just crit me and out-lifesteal me. If I run, he has infinite slows. If I hug turret, he ults then E's. Any tactical trades I make on him feel useless because he can just Q.
