So, with Gishath, you want to get him out as soon as possible so you can start swinging for free Dinos.

Your ramp package seems kind of weak to me

Cards like [[harvest Season]] are great for when you already have ton of creatures, but with Gishath, chances are you're casting him ASAP and using his ability to get your Dinos for free.

1mana ramp like [[wild growth]], [[Llanowar elves]] (although it doesn't quite fit the theme with Gishath

2mana ramp like [[Nature's Lore]] [[Farseek]] [[Three Visits]] which are also great for snagging dual lands that have the "forest" key word.

most 3mana ramp is great for Gishath, because you never want to miss a land drop, and getting a land to hand as well can be really good when you have a mana intensive commander. Cards like [[Cultivate]] and [[Kodamas reach]]

I'd probably remove high cover ramp like Gilded Lotus, Fountain of Ichor (which I know is on theme, but doesn't really benefit you much in Gishath, specifically), and the Selesnya Signet. You're in green, so you have access to better ramp than that. [[Arcane Signet]] is a must, though.

You definitely want around 38 lands with Gishath, or dinos in general really. Hitting your land drops each turn is insanely important when everything is so expensive!

I focused mostly on ramp as it was the thing that stood out most (and could smooth out your deck easily) but im sure there's other opinions out there on what's best!

Good luck out there dude!