I would NEVER advertise it as free. No expressions like "chat for free" "watch free cams".
I would search for quality quests. Using the words "premium" "exclusive" or "real private experience". I would NOT let more than one member on private.
I would limit free chat. If someone needs more discussion he would be able to do it in a pay/message system - if the model turns it on.
If a member has been banned too much times - he is kicked out from the site.
I would make rules for models too. Example the no nudity on free thing. This is important. Of course I would make rules about image quality etc.
Would be contet selling option there. Gifts tips - yes.
Models would be able to send gifts - pictures, videos, winks, kisses etc. But asking for it by a customer: strictly prohibited - causing permanently ban. I would make notifications for it like this "This customer has spend ***$ on you in this week/month/period/...". I have more ideas ..
