I would agree with this
Social media is great, but don’t let it take the place of more traditional forms of networking in your professional life.
When the opportunities present themselves, attend conferences or other events where people within your field are likely to attend. Strike up conversations and be social with others. Don’t be afraid to offer a business card or suggest meeting up for lunch if your new contact is ever in your area. The more effort you put into in-person networking, the more effective your overall networking efforts will be.
I’d also add that social media can assist you when it comes to in-person networking. Going to a conference, for example? Start posting to Twitter about it, and following others who are talking about it as well. Then when you get there, you already “know” some folks and have less trouble trying to introduce yourself to total strangers, which for many of us introverts, is akin to sticking needles in our eyes. 😉