Here are my keys to success...
1) Consistency - I log in daily to the networks that I am involved with. The first thing I do every morning is clearing out my inboxes and making replies to messages.
2) Targeting - I focus on networking with people that have things in common with me or have a need that I can fill.
3) Filtering - I know how to quickly identify and weed out people that are looking to waste my time.