I must admit that these pictures are from this spring, when my worm bin was happy and healthy. I have since let up on the maintenance and lost my worms. But this is a pretty good picture of a happy, healthy worm bin.
The worms are feasting on all kinds of things -- tea leaves & coffee grounds, fruits & veggies. I don't feed them any meat or processed foods like bread, although some people do and it works fine. I also generally don't put in corn cobs, avocado skins, or any pits from avocados/other fruits, since the worms don't eat them and they take forever to decompose. And I limit the amount of citrus, which worms don't like much.
I got this plastic bin from goodwill for a dollar. It already had holes in the side, which you need so that the worms have air flow. I punched a hole in the bottom right corner, so that the "worm juice" (liquid worm castings) could seep out -- I put a yogurt container below it, which you can see on the right there. It's very user-friendly, and right outside my front door. I've since moved it a short distance away, in a shadier spot.