By Charles Purdy, Monster+HotJobs Senior Editor

Whether you're looking for a job or trying to advance your career, networking is very important. And networking shouldn't end when you log off LinkedIn or head home from a conference.

Valuable contacts are on the perimeter of your social circle. They're the parents of your kids' school chums, they're sitting next to you on airplanes -- basically, they're all around you every day. So how do you turn these people from relative strangers into valuable network contacts?

Step 1: Identify Good Contacts
  
An effective professional network has a wide variety of types of people, including people from outside your industry. So how do you decide whether someone you meet at a cocktail party is someone you want in your circle? Career expert Liz Ryan says it's more about "feel" than logic. "You've got a certain style and approach, and people who are comfortable with you and with whom you're comfortable will make up your A-list for network cultivation," she says.

Look for people who are active in and passionate about their field (whatever it is), and who seem interested in what you're doing. Also, people who communicate well are likely to be "connectors" who have their own networks that you may be able to tap.

Step 2: Manage Your Contacts
  
Productivity expert Stever Robbins, author of Get-It-Done Guy's 9 Steps to Work Less and Do More, offers tips for managing the business cards you receive:

First, if you're at a conference or a similar event where you're receiving a lot of business cards, Robbins suggests jotting down quick memory-aid notes on the backs of cards -- so when you enter the contact in your digital address book, you can record (in the Notes field) the name of the conference and what you talked about.

Then, immediately after you put a new person into your address book, send a brief "Great to meet you" email -- with a note about your conversation and a brief follow-up.

Step 3: Offer Value
  
Effective networking begins long before you need to get something from your network. First, you must demonstrate that you have something to offer -- this builds a foundation of goodwill. Every time you talk to someone in your professional network, you should ask what he is working on, so you're aware of the problems your contacts are trying to solve.

In his book Well Connected: An Unconventional Approach to Building Genuine, Effective Business Relationships, executive coach Gordon S. Curtis offers suggestions on how to offer value to a new contact: Consider how you could supply information, new clients or interesting products -- or even other contacts. "If you make the right introduction, both parties will feel you've done them favors," Curtis explains.

Step 4: Stay in Touch
  
Your efforts to meet, record and court new contacts are wasted if you let relationships lapse. An effective networker is participatory and involved.

Sound like a lot of work? It doesn't have to be -- in fact, your networking efforts shouldn't take a lot of time. Read an interesting article or book? Ask yourself who else might benefit from it. Planning to attend an industry conference or networking event? Find out how you can get more involved. Have something to say? Update your blog, and comment (thoughtfully) on the blogs of people in your network.

Step 5: Get Back from Your Network
  
If you've been conscientious about maintaining connections with your network, asking for something like an introduction or a favor will seem less like an imposition.

One key to getting results is to make specific requests of specific people. Sending your entire network a tweet saying, "My interior-design firm is accepting new clients!" probably isn't enough -- because it's not speaking directly to anyone, and it's not offering a tangible value. A better tactic is a targeted message to the right people -- for instance, an email describing your expertise in decorating boutique-hotel lobbies and asking for an introduction to a contact in the hotel business.

Be concise with your requests, don't pester people and don't take it personally if someone isn't able to help you -- the reasons may be beyond his control. And finally, don't forget to say "thank you" -- if one of your contacts finds a way to help you, look for a way to help him, so your relationship will grow even stronger.