For some general jamming tips:
- Have everything updated and ready to go. Check that Unity (or your engine of choice) is up to date. I like to set up a 'blank' project with all of the packages installed and folders set up.
- I personally don't like planning ideas before the jam for a few reasons. Firstly, the theme is an absolute wild card, and whatever idea you have likely won't work with the theme. Secondly, the theme is a useful limitation to coming up with ideas. It's really hard to pinpoint what your favourite food is, but it's easy to identify your favourite pizza. That's because limitations can focus your thinking, and it gives you a solid spot to start from.
- Take time coming up with a game idea. A game lives and dies by its core ideas, so I typically spend multiple hours brainstorming. Even once you've got your winner idea, brainstorm some more, you might find something even better. Also brainstorm ways you can improve that idea even further.
- Imagine yourself physically playing your game idea. What does it feel like to control the game? What do you do, and does it seem like fun, just by thinking about it?
- Then, cut your game idea down as far as possible. The ancient gamedev proverb states that you should 'Divide your game idea in half, then half again'. We all over estimate how much we can do, and this suggestion really is golden. It also helps to create a tight experience, focussed on a few strong ideas.
- Get some sleep, especially early on in the jam. It's a week long jam, so it's more of a marathon than a sprint. If you knock yourself out on the first day, then you won't be able to perform on later days.
- The last day or so should be reserved for final touches. If you're still adding stuff on the last day, then it's probably time to start considering what to cut. Use the last day to polish your game to perfection, add more levels and PLAYTEST.
- And finally, leave plenty of time for submission, particularly if this is your first jam. If you're super fast, it can take as little as an hour, but things almost always go wrong, so it's a good idea to start submitting around two hours before the deadline.
Hopefully these tips help someone, let me know if any need clarification!