Don't try to make a bug or impressive game, make something that works and that you can be proud of.
Game Jams are meant to be fun so don't stress yourself!
You can't do absolutely everything so consider using free assets or buying them instead of creating new ones and working with someone who has experience with art, audio or game design.
Aim to submit 12-18 hours early so you have a stable game running by then. This gives you time to add a fancy title screen or similar luxuries and if you are behind schedule you have enough buffer.
MAKE BACKUPS.
Have fun and I am looking forward to your game :)