Here is my tips
Get creative, don't have your auction this year look like last year, look for more personal items rather than national GC, some are ok, but they are usully small and take just as much processing andend up having to be packaged becaut they never bring full value. look for cool ideas like vacation homes, look for air miles, look for fun way to sell items, bowling CG, ice time, local hotel pool, paired with a homade birthday cake and pizza can be a ton of fun for a pre made birthday party, trips out to movies or lunch with a favorite teacher can be fun for any grade...
MAKE YOUR DESCRIPTIONS FUN!
sell sell sell! Let people know the wonderful thigs they could do with their item. i try never to use the words gift certificate in a description and I never put a dollar amount in a description
My other tip is to hunt and peck with web searching and see what other schools have going there are a ton schools and companes using online websites, it may not be what your school is doing, but you can certainly get some idea of things that would work for your school!