On the "what to make into a TB" question, I have created most of mine out of swaps that have looked interesting or just would make a good TB. I have also made one out of a copy of my own dog id just because it was a little special to me.
In regards to TBs, it is very much anything goes. However, I think it is best to try and keep them small, the smaller they are the more likely they can be placed quickly.