Thanks for the tips.

• Runes: Greater Quintessence of Health > Greater Quintessence of Gold in all situations; you can also consider Greater Seal of Health
• Items: A full build example is never a Core Build so part it in early core items like Sightstone + Talisman of Ascension + Sweeping Lens + Boots and you should mention your starting items: ... + Greater Totem; Warmog's Armor is a selfish choice and you miss out things like alternative boots, Mikael's Blessing and probably Zeke's Herald
• Skill Order: You cannot max an ability at level 8 and you should max your secondary ability at level 13; besides, you can consider maxing Death Sentence second or maxing it after putting 1-3 points in Flay if you feel confident landing Q
• Masteries: Your utility Tree is impossible because you need to select Alchemist to get the tasty cookies. Put three points in Summoner's Insight and due to this oyu can consider 0/14/17 Masteries or even 9/21/0
• Guide: Coding, expand Content ...

icons mid sentence is distracting and poor use of coding. use them at the start of something not in the middle

you also have walls of text at the bottom of your guide.

you should look into adding columns and finding a better way to present your information

You could use some codings like:
instead of pictures

and it will become:

Thresh and