In the first place, what is networking?
Networking is not applying for a job. It is interacting with others as a means to obtain professional information.
And why is it an essential part of anyone's job search?
Because it may be of great help to get information about:
How should I behave in a networking situation?
One interesting fact that is often overlooked but should be kept in mind is your personality. For example, acting extroverted when you are introverted may make you feel uncomfortable and, thus, less assertive. So it is advisable to create your style with which you feel comfortable and stick to it.
And, for better results, it is relevant to prepare yourself in what you want to disclose about yourself and the insights you mean to obtain from others. For example, it may be helpful to be clear about the kind of job you are interested in, in what field and company, where you would like to work, how much experience you have and the training you need, etc.
Who should I include in my contact list?
Once you are prepared to get out there, it is time to work on your contact list. Do not leave anyone out, from friends and family members, neighbors, to people you may know from community groups, school, college, present, and previous jobs, including but not limited to coworkers, supervisors, and managers. For instance, a colleague or mentor at your current job might lead you to job opportunities inside the company, not yet posted.
Offering your help can make your existing and new relationships more solid and lasting. Helping others will make them willing to do the same in return, which can become beneficial for both.
Where should I reach people?
It is easier to contact people you already know. To get to people you do not know, join groups and discussions related to your professional interests. Do volunteer work. Online networking is also beneficial. Linkedin, Facebook, and Tweeter are among the most popular ones. Just be sure to know about those groups you join.
Organize your contacts to make their follow-up easier and practical.
And finally, keep a few business cards –concise and straightforward- and resumes handy. You may need to hand in one at any moment.