Know why you want to network. Is it to raise your profile, create new opportunities, build alliances or just to be well informed? When you are clear, you do it well.
Be subtle. Great networkers are rarely considered as such, but as interesting and interested individuals.
Keep abreast of current affairs. It helps to generate interesting conversation and gives the impression you are on top of things. The same applies to what is going on in your business for internal networking.
Do your research. Asking someone if they know a company well and being greeted with the reply 'I used to be their chairman' is more than a little embarrassing.
Say more than just your name when introducing yourself. Add something to help the other person continue the conversation and build a connection.
Ask questions. People are more engaged when they are talking and being listened to. Proper interaction also provides an opportunity to spot mutual interests.
Bide your time. Hold off on your critical question (or favour) till you're sure the relationship is good enough. If you've built rapport there are sure to be other chances.
Follow up. This is where supposed natural networkers fall down. Do whatever you've committed to doing; send a follow-up e-mail, invite them to a suitable event, and refer back to the conversations that you have had.
Keep trying. The more you practise, the better at networking you become and the easier it is. The knowledge economy is being replaced with the networked economy. If you want job security or a meteoric career, building effective networks is a great way to achieve them.