Initially, communicate by first name only. Talk to people over the telephone before meeting them in person. If you arrange a meeting, make sure it's in a familiar, public place, such as a busy restaurant, where you won't be alone. If possible, carry a cellular phone, and let a friend know where you're going. Dating services will often screen clients, as well as act as a clearinghouse for personal contact information, such as phone numbers and addresses.
Clients can choose whether and when to have that information forwarded.
There are also those who have a sexual obsession with people with unusual physical characteristics or disabilities. If a new acquaintance's questions seem strangely slanted, be on guard.