This was only my second jam, and I learned a ton. For my first jam (which was only a week), we BARELY finished on time and our game was super buggy. So going into this jam I decided to plan to have the game done a full WEEK before the deadline because I expected to fall behind. Sure enough I did, but because I set such a hard deadline I still had my MVP finished and reasonably clean 3 days in advance and had a decent amount of time to clean up and polish. I'm happy with how our game turned out, but there were still quite a few features we had to cut, so next time I'm gonna plan for even more polish time.
Also, I had a team member that was super new to Unity, and I assigned him a pretty decent sized chunk of the project. Because he was new he needed a lot of help and I had to spend more time than I expected helping him with his part. So I also learned not to expect too much from others (or even yourself) if they're too new to Game Dev.
I made Dog Days btw, please check it out and tell me what you think :)