They treat their interactions with candidates as sales and marketing activities. They take the time to sell you on working with them -- by being patient with you, focusing on your needs instead of their own, and avoiding the temptation to launch into a list of vetting questions when they get you on the phone.
When they set up a telephone, Skype or face-to-face meeting with you, they keep the appointment the way any business person would. If they're going to be late, they let you know.
When they ask for your resume, they tell you exactly why they want it -- for instance, to send it to their client at Angry Chocolates so the client can consider you for an open position with the company.
When you do something they've asked you to do -- sending them your updated resume, going to an interview or referring a friend for another job opening they're trying to fill -- they acknowledge your action and thank you for it. They don't take you for granted. Without talented candidates like you, a recruiter cannot earn a dime!
After an interview, they get feedback from the employer within two or three business days. A recruiter who says "I haven't heard anything from that company -- I guess they're not interested in you" is not someone who is qualified to carry your flame!
They are honest and compassionate with you. If they don't think you are a great fit for a position you are interested in, they'll tell you so -- and tell you why. They don't play games with you.
They don't tell you they need your salary history in order to work with you. That's not true!
If they don't have a suitable job opening for you right now, they'll say "That's okay -- let's keep in touch" and then they really will keep in touch. You need to keep up your end of the connection, too, and let the recruiter know if your job situation changes.
Their biggest concern as your representative is to put you into a new job that will expand your horizons and grow your professional portfolio -- not just any job that they happen to have available.
Above all, they listen to you instead of telling you how to think or feel.