Exchanging business cards with strangers isn’t the only way to build quality connections. Instead, ask friends if they can make introductions, reach out to someone on social media to see if they would be willing to hop on a 30-minute call, or go to non-networking events such as hackathons, where there is still an opportunity to meet like-minded people in your industry. Some of the best opportunities to network are those social occasions that you might get dragged into, like BBQs, neighborhood mixers, or even your kid’s school PTA fundraisers.

(Source: http://insights.dice.com/2015/10/08/5-professional-networking-tips-for-introverts/)