I'm also a 'bit' new to game jams so take my tips with a grain of salt. These are just my opinion
Try not to over scope, its fun to finish something to get feedback afterwards, so make sure its something you think you can finish.
Dont be afraid to try new things, jams are a great time and place to learn something new, that you might have no experience making.
There is a program called sfxr that will randomly generate sounds for you if you not sound savy. Sound design is what I usually do last so its a niffy program.
Give yourself some time for polish if possible, its a fun part of the process I find and it can take more time than one might think.
Enjoy yourself, do not get too stressed about it.