One of the best ways to prepare yourself for judging Developmental competitions is to visit the Education Page of the NGJA website.
http://www.ngja.org/education.html
This resource provides videos and routines analysis for JDP, NCAA and FIG levels. You can do this by yourself, work in a group or consult with other judges or coaches. Have fun and see how you compare to NGJA experts!!!
Below are help sheets that include the most common FIG skills performed at Junior levels: