All you need is good positioning, good runes and of course a good lane partner :) (unnecessary).
I won't stall, look down.
Focus on maxing E (Flay), because of the insane passive damage.
After that W (Dark Passage) for survivability. (I don't really know how to spell that :D)
Then Q of course.
Maxing R as all ultimates.
Thresh has slow attackspeed, so focus more on the attack speed items.
Start with: Doran's Blade
Rush for Infinity Edge and Phantom Dancer.
Final Build: Berserker's Graves (Homeguard), Infinity Edge, Phantom Dancer, Statikk Shiv, Blade of the Ruined King, Bloodthirster (After you think you have enough attackspeed).
9 Attack Damage, 9 Attack speed, 9 Armor or Magic Resistance, 3 Attack Damage.
For me it really doesn't matter if the runes are from Tier 1 or Tier 3, they just need to be the right ones :)