The runes you mentioned aren't standard anymore.
Going 9x Greater Seal of Armor and 3x Greater Quintessence of Health gives you 9 armor and 78 health. But if you go with 9x Greater Seal of Health and 3x Greater Quintessence of Armor, you have 72 health + 12,78 armor, which is better.

Your starting items is weird. I would recommend Relic Shield/ Ancient Coin + 3x Health Potion + Stealth Ward or Relic Shield/ Ancient Coin + 2x Health Potion + Stealth Ward + Stealth Ward. With this you can last longer in lane and be more aggressive.

You should mention Relic Shield as well, only having Ancient Coin is really bad. I see no mention of Frozen Heart, even though it could be better than Randuin's Omen after the last patch (only in some occasions), and Banshee's Veil would be more effective than Spirit Visage IMO.

I don't see any information on supporting even though your guide says Supporting as Thresh. Overall I think your guide has a lot of weakness and doesn't add new or important information on how to play thresh/support.

Actually some high Elo ADCs have stated that if you run Barrier and support runs Heal you can't be killed in the early-mid game. This works in weak comps.


To the guide:
I prefer 0/21/9 or 9/14/7 or 9/21/0 runes myself

Max an ability by level 9

Ancient Coin is the only starting item in the guide and I heavily disagree

The seals and quints should be the other way around

lacking explanations on masteries and items and gameplay in general

Heal is a better choice for AD Carries thus you should run Exhaust or Ignite on a support. Mathemetically Seals should be Health and Quintessences Armor, I don't run it myself because I don't want to spend that much Influence Points into that. Boots of Swiftness is kinda odd to me in comparison to early Mobility Boots which are way cheaper and increase your pick potential a lot. Instead of you maxing abilities in no real order you should max out Death Sentence or Flay.