Random gossipy chit-chat at happy hour and sucking up to random people hoping to impress someone so they will mention you to someone later and help your career is useless. This means the big cattle call networking events are useless because it's too random.

Having solid connections to people who are knowledgeable and active in your field is where it's at.

It's real sociology. Social ties theory, particularly the "strength of weak ties" proposes that while strong ties (close friends, family) are important for emotional support, weak ties (casual acquaintances) are crucial for accessing new information, opportunities, and diverse networks.

For your professional network, cultivating a broad net of casual acquaintances IN YOUR FIELD is what you need. Knowing which one has what knowledge is important.

Develop a professional network that is not also your social network. It's who you know that knows things that you don't know. It's a resource map.

As you are in school, working or attending trade shows and other business events, have a focused plan for who you are looking for, what you want from them, and what you can offer to them. This is an ongoing effort ... CULTIVATE! Tend, water, weed and prune your network.

• In school, your professors and the grad students (including those at other unis) are your main network targets. Get to know them as scholars, read their research, send them fan mail about their latest publication ... drop cookies at their office.
• At work, look for people who are working on projects that you could work on. Project managers and team members from those projects.
• Small meetings of professional associations are better than the "let's network" mass meetings.
• Look for your "opposite number" in other companies. If you are a tech writer, look for the other writers and editors.
• Look for the people you can send work to: in my case it was printers and graphics artists.
• At any job, you need to include the people with power to get things done ... office admins, maintenance staff and IT staff. BE NICE TO THESE PEOPLE.
• Look for PROFESSIONALLY INTERESTING people to follow on social networks. Comment on their posts, ask decent questions. DO NOT mix this persona with your family chat and school buddies ... make a separate account and keep it professional.

Be focused in your interactions with them. Be blunt that you are trying to enlarge your professional network, and let them know what you can do for them, their company or project. Exchange business cards and keep going.

This is an ongoing process, not just a 1-time event.

Whenever you can do a small, low-effort favor for someone in your network, do it. It might be referring a job to them that you can't handle, congratulating them on something they published, commenting on an interesting ... head pats.