I try to answer all emails (even cold calls). I have the highest opinion of those people that take the time to say "no thank you". Jim
The bottom line in networking is building a win-win relationship. The habit I use most is speaking. For example, I'm speaking to a group of clients at a seminar that a financial advisor has...I bring value to his clients...while meeting potential clients for myself. I also will be doing this for a lawyer who helps entrepreneurs speaking at a seminar to his clients. I'm not charging them a fee as this is part of my networking strategy.
Building up relationships first and that may include small things like wishing b'days and keeping in touch with Gentle Hello messages.
Asking for suggestions (with an eagerness to implement as appropriate) and inviting people to be volunteers and a part of beta testing of products and services at lower pricing has worked great too.
Any networking habit that makes other personal special or important works well.