Thanks for the constructive response, this is my first guide so I will be editing it and refining it. Did it pretty quickly to be honest, also I don't ever really feel the need to have defense masteries when I build tanky with Leona, her W and my rune setup work well for giving me some resistance, I use a different page for other supports but I find this works well. I did say if you want you can go more in def masteries but that I find this works for me.

Items: Good, missing a LOT of situational items though.

Runes: They're fine. Missing a few optional picks.

Masteries: Why are there zero points in defence? I can see a full utility build being viable, but still, missing a lot of different masteries.

Skill Sequence: Don't get Zenith Blade at level 1. Just don't. Also, your maxing is irregular. It's usually 9/13/18, here it's 10/13/18.

Guide: Terrible. Walls of text, no images, no formatting, and pitifully short.

Sorry, this doesn't get an upvote from me. You have a good base, just develop it.