|These violets are less than an inch tall and photo was taken with a lightbox and average camera.|
In the video below, T-shirts are used to diffuse lighting. If you don't have some nice white T-shirts to spare, other options are white gift wrap tissue, wax paper and similar translucent papers.
Note: I made a box similar to this a while back and it worked OK...however, I found it so useful I went ahead and purchased a sturdier setup like the one below (on left). Inexpensive, folds up compact and includes folding lights!