It doesn't matter if you are seasoned or not, just follow the DMOZ guidelines for suggesting a site. You won't do very well by skirting the guidelines or making up your own interpretation.
No, not at all. Just look at the websites alredy listed, do research in other words. It is easy to pick live ones rather than dead ones. Also try to put yourself in the dmoz editors shoes. We know the ones that would be picked, and don't submit till it is a year old and registered for max length LOGIC
i gotta say you are extremly lucky on this. some ppl have submitted years ago, never got listed. so congrats mate