Make sure that your game is playable in browser. Also it's important to make a good thumbnail - more on that here. One thing that usually annoys me / puts me off from trying out a game when I browse itch.io is the lack of screenshots and description which are visible when you highlight a game on itch.io (thanks to them you can see/read what the game is about without opening it's page, which highly increases the chance of your game being selected by potential players from among hundreds other ones)
Viewing post in Tips to get more reviews?
That point about making sure your game is playable in the web browser is an excellent one, and I've overlooked it in the past.
With a web-based game it takes less time for reviewers to start playing, and it gets around the issue of not trusting the software that you download from strangers. Plus, it makes the game accessible to a broader player-base than just Windows.