For this costume, I started with the idea of putting Tinkerbell in a lantern - like after she is captured by Captain Hook. We have lanterns at home that I used for the design.
The lantern I made is made from cardboard. I closed in three sides of the lantern with clear sheets of plastic. These plastic windows are from glazing taken from poster frames I bought at thrift stores. The plastic could easily be cut with scissors or a razor blade. I taped the cardboard together, then paper-mached and painted over that. Then I installed the glazing windows.
Tinkerbell's outfit is made with a green tulle skirt and a satin top. I did not use a pattern, but there are many commercially available patterns for this type of costume.
However, anyone with basic sewing skills could easily make a simple Tinkerbell costume like mine.
I made the wings out of wire and nylons, but most dollars stores sell simple wings like these.
I bought shoes at a thrift store and painted them green and glued on white pom poms.
Our toddler loves playing in the lantern and is still using it now that Halloween is over. She likes to sit in it and watch Disney videos!