Put your contact information everywhere. Make sure your emails are signed with your phone number and other relevant contact info. Your blog, twitter account, facebook, business cards, voicemail, and everywhere else you have some sort of presence should have this information in an easy-to-find and obvious location. The slightest difficulty or inconvenience is enough to send a prospect elsewhere. If you are out of the office, even for a short period of time, and can’t respond to an email, create some sort of auto-reply that has another way to contact you along with information detailing when you will be back.