With networking, follow up is everything. The sooner and better you follow up, the greater the chance you'll reinforce the positive first impression you should have made.
A same day/next day follow up e-mail or brief phone call work very well. With the call, briefly reintroduce yourself, mention where you met, indicate that you want a few minutes to continue the conversation, ask if this is a good time and ... paused for the other person to analyze and respond. In so doing, you'll display 'uncommon courtesy' and class.
Best wishes for networking with more Power & Success!
Phil Stella, MindSpring Networking Editor and president, Effective Training & Communication, Inc.