I've had a Worm Factory bin for over a year now, and I have a very simple approach to feeding the worms: whatever yard or food scraps (raw or cooked) that I would otherwise throw away in the trash, as long as they are soft enough for me to bite in and cut in small pieces. The only exception is that I also add crushed egg shells.

I've never had a problem with the smell or flies (maybe because I keep the bin at around 55-60 F), and the worms seem to multiply nicely. I also almost never use bedding and / or "carbon sources", except with the occasional egg carton. Question: should I? On one hand, people say I need a carbon based bedding. On the other hand, my bin seems to be doing well without any, plus I'm suspicious of chemicals used in making cardboard / paper.