I answered
a similar question in the past, so that may be worth a read. But here are some more off the top of my head:
- Presentation: You don't have to be great at bbcode, but a few pictures here and there and nice formatting will usually lure in more players.
- Having a vision: Unless you're going to do a sandbox RP, it's always good to plan ahead For me, that means having a beginning, middle, and end in mind. It doesn't have to be set in stone, of course, because things may develop differently in IC, but having a vision gives direction and drives the role-play forward.
It's also good to set some rules and figure out what kind of role-players and posting speed you would ideally like to have.
- Action: First posts are always difficult, which is why I find it best to introduce conflict/action to my players as soon as possible. Start things off with a bang.
- Momentum: Keep spicing things up with conflict now and then. Move the scene forward as soon as things start to get boring.