Invis heroes are difficult to counter for newer players because it's harder to see their weaknesses. Gem is pretty much always the right choice, but it'll require you to make few mistakes during your early pushes, and you have to make the right choices in your early decision making.
The Purge Casts a Pub series is made to entertain and educate you on the ways of pub mistakes.
I go over their skill builds, talk about why they are crappy, and talk a little about execution(but not very much because the skill level is pretty low anyways).
This is episode 19 of Purge Casts a Pub! In these I talk about build and item inefficiencies as well as talking about mistakes made as a team. I will try to find another super low level pub game to cast later, so I opted for another "high level" one. Thanks for watching!