While the small box type worm farms i had made were quite successful, I found it all a bit fiddly, so i converted an out door cabinet I had (mainly full of old pots and other junk). I didn't bother adding drainage holes, since it wasn't perfectly sealed, or airholes, due to the size. I just dumped a load of composted vegetable matter in and let them get on with it.
6 months later I have about a cubic meter of very moist worm castings and a population of worms with a very wide age structure, suggesting to me that they are breeding successfully. I emptied the other bins in and have now just started using my mega bin:
Inside the bin I have laid cardboard and plastic to retain the moisture:
Under the plastic are many worms: