I suggest enforcing a small booking fee or deposit, it usually weeds out a lot of timewasters. I used to get a lot of timewasters and NCNS when I didn't have a deposit requirement. It's been so much better since I started requiring it a couple years ago though.

I'm 100% outcall now....but there were few times I've offered incall before (in and out of town), the only guys who followed through were the deposit paid ones. The others always just ended up ghosting, which sucks since I used to hold times for non-deposit people for so many days...

My deposit fee is a flat $50. I always inform everyone it goes toward my rate as well, which many (if not all) like that (instead of it being a fee in addition to).