Dos and don'ts of networking. Do always bring business cards. Always remember to follow up with an email afterwards saying, "Nice to meet you." Do file their contact information away right away. Don't wait because you'll forget, and when you do file away their information in your Rolodex, makes notes. Remember what you talked about, what they do, what they look like. Do invite them to your next appropriate event. Follow up with them about setting up drinks or dinner, or lunch or something like that.
However, there is a fine line in networking. You don't want to be overly anxious. You've got to find that balance. Don't be too pushy. Don't multiply email them. Basically, the one email, "Nice to meet you," and then follow it up maybe the next month inviting them to a cool event that you think that they would like, remembering something that you guys talked about because you made those notes.
That's the way to successfully network and create a relationship with somebody without being too pushy. Please, don't email them weekly. You've got to find that balance and then you will become an excellent networker.