I am new as well and have never successfully finished a jam and I think that was due to overscope so I would say try and keep it to a smallish size personally I am going to be making a arcade style game
Definitely manage your scope. I usually implement 2 or 3 mechanics and leave time to build levels and test! Use free assets/resources to make your life easier especially if you're running out of time (for things like music etc)
I just finished my first Jam and this are my tips:
-Get up early, have a good breakfast and start (Of course this depends if you work, study)
-Use a game engine you like or enjoy
-Don't be afraid of using YouTube tutorials for everything (Creating menu, how to do this or that)
-Manage your scope, go for something small with a few game mechanics. During jams we don't have much time. And sometimes trying to fix a bug could take a long time.
-Use free assets (SFX, Music, Sprites, etc)
-Take a break when you need to. But keep the focus on the game and don't procrastinate too much.
