I can never stress enough how important it is to network and use LinkedIn. Many industries are very small and it helps to have a foot in the door with knowing people in order to secure a position. Making connections isn't enough, keeping them and staying connected to those people is key to being able to call upon them should you require their aid. LinkedIn is a fabulous way to keep in touch with professionals.
From networking events held by college campuses to interning, you can network with those around you and leverage them to benefit you and your success. A key thing to remember is that a connection is a give and a take. While you can ask for help from those you connect to, you should be willing to reciprocate in kind. People you have classes with, people you intern under or with, your professors, and so on are those you can network with to start. Networking can be a daunting task when you are shy and are new to it. Don't worry, everyone had to start someone so most people try to make you comfortable while talking with you.
I love LinkedIn because it allows me to stay virtually connected with those I've met through interning, at college, and at networking events. The site is a living, breathing resume and allows you to showcase yourself professionally. LinkedIn allows you have a way to keep who you've met with and worked with on hand in order to leverage them in the future. I know several older professionals who have said they used their LinkedIn network to find a position after losing their job when the economy in the United States fell apart. The website has the option to send mail to those you've connected with which can be used to keep in touch if you aren't close enough to email back and forth. It also allows people to see what you've been up to and remember who you are so if a position they hear about fits your skill set they might send it your way or recommend you for it. My advice for LinkedIn is keep it up-to-date, ensure you have a photo, and use the mail feature to reach out to connections you may not deal with on a regular basis in order to keep the relationship open.