You can make sure to have distinctive titles for your games, a good set of tags, and post devlogs. That will help on Itch, but you should do your own promotion as well, on social media and so on.
Beware that Air Ranger isn't going to be indexed, because you're only selling a text file with a Steam key. That's not the way to do it. Please either sell the game on Itch. or else just add a link to Steam on the game's edit page.