Hi!
It is not easy for an entrant with a busy schedule to find enough time to complete the entry. I think that.....
1. Game jam is a healthy activity. Don't put too much pressure on yourself. Enjoy every jam.
2. For the game idea of your entry, keep it simple. Design your game around only one mechanic and focus on making the game look complete. Introducing a lot of features may make the code structure too complex and can introduce many bugs.
3. Make a short game. Since voters may play a lot of entries, most of the voters don't have time to finish every entry. Entrants should focus on giving voters good first-20-minute impressions with their games.