Make stencils

I have seen a few post on different threads about people making their own stencils. I can not seem to find them now but I was wondering if someone can give me a refresher? I have a adult oriented event in 2 weeks and was hoping I could make a few tribal arm tattoo stencils and a few others to help out. I dont know what type of material to use or what you use to cut it. I am crafty but would prefer not to wast to much in trial and error

I have made simple stencils by cutting a plastic pocket folder with an exacto knife! You can either draw your guide lines on with a sharpie or gluestick a paper image down to go by. (it peels up really easily when you're done but stays put while your're cutting) They also sell clear vynal sheets in Michaels that are specifically for stencil making- I'm sure it's easier to cut and more flexable than a folder is, but I havn't used it. OH! and I remember reading that a Woodburning tool works really well for cutting (instead of the knife that only really loves straight lines)

I've cut stencils with scissors, knife, even a hot stencil cutting tool to melt plastic - but this thread really changed everything for me:
http://www.facepaintforum.com/t3113-cricut-and-glitter-tattoos

I invested in a Cricut, the software, and am using different bits of plastic (like from clamshell packaging) or acetate or whatever to make stencils. I can make far more complex designs than I ever thought possible! I am totally loving the possibilities.

If you are cutting them by hand (knife or stencil burner), one trick I learned was to invest in an inexpensive glass front picture frame (like from the dollar store) - place your picture in that, and cut on the glass - then you don't damage your picture, but can still see it clearly.

I've also used hole punches (like craft ones) to produce interesting stencils - depends what you have on hand.