There is a lot of good advice here but I haven't seen this yet and it needs to be said:
There will be A LOT of people here submitting games that are way beyond the skill set of beginners and anyone who is just getting into game dev. This people love to have their ego stroked and will submit games to show off in any large game jam.
Please do not get discouraged by this! I guarantee you, that if you are paying attention to the submission feed and comparing yourself to teams of experts, and you are solo... you will get your feeling hurt and be down on yourself... DON'T! Keep your head down and don't focus on trying to compete with everyone else.
The point of this event is to HAVE FUN!
If you submit a game and don't get many plays, just spread some positivity and good karma by playing the many other submissions that have put just as much, or maybe even more time into theirs. You will feel just as good giving compliments and giving others the satisfaction of having their hard work not go un played, than as you would receiving it. You get what you put out in game jams.
Oh yeah... one last thing, if you play someone's game, leave a nicely toned compliment in the comments, and maybe save the feedback or bug reports for a private message or discord? It is all to common to see people taking these game jams way too competitively and start commenting all the other games faults and bugs, to have your comment section detour others from enjoying your game. ~ You can always be kinder when commenting. Lift each other up, instead of knocking each other down. ~
Good luck everyone! Remember this is for fun and not to make it a toxic imaginary competition of commenting mistakes, when this is just a group of people trying to make friends and have fun together...