I want to start making my own skirts so should I tie them with a wire or just use rubber collars?

Check these videos out.  I prefer wire tied myself. 

http://www.bassresource.com/bass-fishing-videos/how-to-tie-jigs.html

http://www.bassresource.com/bass-fishing-videos/making-a-jig.html

I do it all three ways.  Todays bands are a lot better than those of the past.

If you are one of those guys that like to change skirts on the boat then I would use a rubber collar. If you never change your skirts and want a secure skirt then I would hand tie with wire.

I tie my jigs with kevlar thread and I also intend to try used braid at some point.

I like to make my own spinner baits for night fishing and have been using the small 4'' zip-ties to secure the skirt material , for several years now. Never had a problem with the skirts pulling off, the material pulling out or the zip-ties breaking.