I have struggled with this in the past as well and have found that in the interest of trying to be considerate to Prospect #1 I have told Prospect #2 that I needed to contact Prospect #1. I then call and email Prospect #1 and wait a couple days. I either don't hear anything, or I hear that they've hired someone else. I then go back to Prospect #2 and let them know the good news that I am available, only to be told that while they were waiting on me to hear from Prospect #1 they have hired somebody else as well.
This has happened a couple of time and I now tell every prospect that I talk to, "I'm not trying to put pressure on you but just so you know, a signed contract and deposit is required to book the date." I love treating my clients like family, but I also have a business to run.
DaveHoyt