If I was camgirl, my resume for the job would look something like this. The stuff in bracket is just an explanation.
Self-Employed Internet contractor. Designed and executed marketing campaigns to drive paying customers to my storefront on an international web sales-of-services platform. [I’d call a camsite an ebay of services] Increased monthly sales by X% in N months [your beginning camming income compared to your peak income.] Top 1% in sales for Y months on website [If you made top 250 you are in the top 1% of MFC sales] Made extensive use of social networks, including twitter, instagram, tumblr [whatever you used] to reach new customers and drive traffic. Reached a peak of X,000 twitter followers [or whatever your most impressive social network stat is]. Customized my storefront using HTML and CSS [If applicable] including creating graphics.... [add a blurb about whatever art or multimedia]. Developed promotions and customer acquisitions and retention programs [raffles, games, and clubs respectfully].
Provided email and chat-based costumer support.
There are actually a lot of valuable business skills you pick up camming and I'd definitely highlight them on a resume. People do get fired for lying on a resume and this is 100% truthful, if deliberately vague as to what you sell at your storefront.
Now what you say at interview is up to you, but the purpose of the resume is to get an interview.