AP Heavy Ivern curbstomper
Hello, this guide will give you an understanding of how to achieve a higher damage output on Ivern, the Green Father, while not being terribly easy to kill in the process.
I've found flash to be helpful overall but you are welcome to take ignite or exhaust in place of it if you feel your positioning is good enough and that you can juke important skills, both of which are good for powerful early ganks or shutting down priority targets like igniting Mundo during ult or exhausting a Rengar trying to take a bite out of someone.
Keep in mind that Ivern has the easiest time with a level 1 invade. I suggest going to the buff that you think the enemy won't be at and stealing it, then proceeding with the standard clear of your own jungle. If you stole blue, farm, and if you stole red try for a level 2 gank if possible, but Ivern does need blue buff early to do his clear and will also need all 3 potions in most situations.
Creeping / Jungling
I recommend with the new season to prioritize buffs first (as always) then raptors and to not bother with the krugs much because you only get 80 gold as Ivern since he doesn't get the broken down krug gold or experience thus making it a very lackluster grab while also most of the time being out of the way.
During ganks you want to apply pressure more than anything. Sometimes putting a bush on a wall alone can help your team without you even staying there. Try to use the sweeping lens and oracle's on more committed ganks or to deward dragon.
On topic with Dragon, Ivern is not good at taking it alone, however if he gets a successful gank bot his team and himself can take it with ease and with little risk of it being stolen if he puts the dragon and his allies in bushes so that the enemy can't see the dragon's health even if they have vision.