I find that too many Recruiters are hiding behind the computer. Do not be afraid to hear No or an answer you do not want to hear. Picking up the phone builds the relationship between you and the Client and you and the Job Seeker. Email can be a useful tool and complimentary tool but I believe your main source of communication should be the phone.
My challenge to you: Use the phone for everything for a month, change your habits and see how many more relationships and placements you can make. Stop hiding and let your voice be heard.