a little late to post this, but here’s a good list of articles full of tips for jams.
http://gamedevelopment.tutsplus.com/articles/16-tips-tools-and-resources-for-your-next-game-jam–gamedev-12084
http://indiestatik.com/2013/11/20/game-jam-advice/
https://www.gameacademy.com/why-should-you-participate-in-game-jams/
http://www.gamasutra.com/blogs/TaroOmiya/20130124/185438/Some_advice_on_Global_Game_Jam_2013.php
http://www.gamasutra.com/blogs/SamCoster/20130130/185766/5_Things_Jamming_Teaches_You.php
http://www.funstormgames.com/blog/2012/06/designing-around-a-core-mechanic/
Ithink it will still be useful for those nervous hours before the beggining. =]
