As a member, I won't attempt to tell you what I do. What tends to draw me in to a model's room is the following:
1) Thumbnail on main page: Does this look appealing to me? It doesn't have to be nude, actually I kind of like when they aren't. Nor does it have to be artistic. Just a nice picture that seems inviting of sorts. It can be anything from a screen cap from a show, to a head shot. B&W profile pic, or I've even found motorcycle and bicycle pics interesting enough.
2) From there, I'll do a preview of the room by hovering the mouse over the camera icon to see what's going on. The appearance of your cam area has a big influence on when I enter or not. If it's messy, dark, or something such as body type or something you're doing doesn't appeal to me I won't. If it is, then I'll enter
3) Once I'm in the room, I'll give a few seconds to stabilize before I make a decision. How's the audio and video feeds? If you're playing music, is it something I like? Does it overpower you talking? What's your cam area in a larger window compared to what I saw below? How's your voice (certain voices really drive me crazy. Can be the nicest person in the world. But, if I can't take the voice, I leave).
4) What's the overall feeling of your room? Are you a welcoming personality? It's okay if you don't say "Welcome" to every person entering. But, if I say "Hello", or tip note a hello, so you say something in return? What are your room members like? Are they decent? Or, are the dumbasses making stupid and beligerant comments that I don't appreciate or like? I'm all for a joke, and I know a few really bad ones. But, I hold the line on some things and won't make stupid comments related to certain topics.
There's more to it, and all of this takes place within about a minute's time. But, if most of these are appealing to me, I'll usually stick around for a bit longer and participate a little.