origami makes for good ornaments for christmas trees, but hanging them can be a problem. ordinary thread is too thin, and while it will work, doesn't look aesthetically right. the solution i found for this was to use embroidery floss. the floss is actually several threads coiled into one, and you are meant to uncoil them before use. however for hanging purposes you will want to keep them coiled.
the next trick is to get the floss through the model. the easiest way to do this is with embroidery needles with heads large enough to thread the floss through. you can make this easier by getting a needle threader. all of these are very inexpensive.
!