My answer to this is pretty much the same answer to the question 'what should I build?'. What you love.
If you want to play music, play what you love. The best DJs I hear are knowledgeable of their genres and turn me on to tunes I might never hear if everything is requests and, to be frank, pandering to the crowd.
I understand the business aspect of making folks happy and wanting to get in where there's a market, but if it doesn't start with a passion the folks are going to feel that and feel played not played to
Times to hold events should depend on your needs. I have listened around enough to know there's always someone looking for a party. It is definitely a good idea to scan future events listings in places like the forum if you want to avoid timing conflicts. As we grow, these conflicts will become less of an issue. Everyone can't be everywhere at once ^.^
Play (or have folks play) what you (they) love, build to your taste and even if your first X number of events have only a handful of people or even ONE person, give your all.