Look for clothing that will let light shine through, nothing too thick or dark. When choosing the outfit at a thrift store hold it up towards a light source to see if it will let enough light through. Avoid dresses with thin straps and be aware that dresses with more structure will hold their shape better than flowy outfits.-Lamp base
Ikea's Dudero lamp works perfectly for dresses
Ikea's Not lamp is great for shirts once you remove one section to make it shorter
Both of these lamps, and other similar styles, are easily found second hand on sites like craigslist & kijiji. We paid between $5 and $10 for each lamp.
We were able to do about 3 dresses with one 472 ml bottle of Stiffy (stretched out with glue and water). How much you will need will depend on the size and material of the clothing you choose.
-White glue (optional)
-Plastic wrap or large plastic bags
-Dress form and/or tape
If you don't have a dummy on hand, you can make one by wrapping a volunteer in tape like so
-Wire (a metal hanger will work in a pinch)