My first game jam experience was pretty rough. I joined up with the newgrounds game jam. I went in without knowing anyone, and that year they had a high school gym style team picking system. The designer or programmer picked out their team one by one from all of the people that were signed up to participate in the jam. I won’t recap completely but we totally overscoped, the artist didn’t really do much work, and the whole thing fell apart. We had some really good music though.
My biggest mistake was trying to keep making the game after the jam. It was my first experience working with other people and I have learned since then that its really important to pick the people you work with carefully.