Add social buttons to your game - If someone likes it, make it easy for them to tell there friends
Get your friends to rank and post reviews - I'm more likely to play a 4 star game then a 3.
On google play, I found adding Language Translations to the store Listing will boost the downloads - I don't recommend if your game has a lot text or requires reading to play.
Try to pick a unique name. On Google Play my app Sewer Fish is #1 on the Keywords "Sewer Fish" & "Sewers" and It's #3 for "Sewer". My other game Smash Car title is not that unique and it's hard to find - but I'm working on it. I just started using mobileaction.co to track keyword placement & ASO - it's free
Naji Thank you for writing a review of Smash Car on your site, that helps to.