My number one tip for any game jam is: try and keep it simple. Looking at your profile, I'm assuming you're quite new to game development, in which case I recommend you try and keep it as simple as you can. For this jam, "simple" would probably be making two parts of the same game. Maybe two mini-games you keep bouncing between?
Other than that, I recommend you focus on gameplay first, game-feel second, graphics third. If your game isn't fun to play, nothing else matters, since most people wouldn't bother playing something that isn't fun or engaging. Simple graphics with great polish like screen-shake, effects (both sound and graphics), and animations feel much more alive and satisfying than good graphics without the polish.
If you want a lot of people to play your games, make it playable in the browser, add the controls / instructions to the title screen, and use a couple gameplay .gifs as screenshots.
I hope this helps! If you need some more advice/help, feel free to let me know!
