I used to do it round a full time job, but the need for money whilst important I didn't need to do many as I had a reasonable salary, but in those days I could do one day a week and see lots of men then, I suspect it's harder now starting up.
Then I went full time and had to work much harder at advertising, getting a website and hanging around waiting for bookings. Now I have other freelance work I divide my days between civvy and non civvy, but as I work from home mostly it's easy to see someone in between other work, It's the best of both worlds for me, but I think having been full time for 4 years means I have an established client base who will work around me.
I still have days when I feel disappointed when I've been out all day with civvy work to come home to loads of missed calls and days when I decide will be an escorting day and nothing much happens. I suspect everyone experiences quiet days and manic days, it's hard to control or predict.