There are some great ideas here. I think W. Cary Rowell hit the nail on the head. For any truly relevant connections or conversations, ask for a follow-up meeting. It can be casual or more formal if the shoe fits.

I'd add these few tips:

1. Don't waste your time, or anyone else's, if you can't help them in some way.

2. Be a trusted resource. If you know somebody who can help them or who is looking for what they provide, make an introduction. Even if there is no direct benefit for you.

3. Look for something you have in common. An interest you both have or a contact you share. Reference this in your communication.

Hope this helps!