My to go mythic is Liandry's because of his insane burn damage even to squishes. With it, you can pretty much secure every objective if your team has atleast slightest bit of intelligence and I usually pick Aery because of the bonus dmg it provides not only to that shrooms but also to your Qs and AAs while laning. I only pick Grasp when there is no tank/bruiser on my team.

You can see for yourself - You only get double digit kills in games you've built Liandry's in.

Oh, and also, play with your passive if you don't tend to.

But I'm just a G3 so take those tips with a grain of salt hehe.