Create your profile early and start building a network. Join groups related to your interests and start participating in discussions. Learn who the leaders are in the fields you are interested in and start connecting with the companies they work for and build a professional network for internship and job leads.
LinkedIn is one of the most respected online professional networking sites. Helpful handouts to help you get started with building a LinkedIn profile and start networking with professionals in fields of interest to you can be downloaded at LinkedIn's Higher Ed Professionals site.
Facebook and Twitter
When thinking of how to integrate social media outlets into your professional life, be cautious of what you post. Review your Facebook privacy settings and remember that potential employers can access your site through shared friends, interns, and other personal connections. Be sure that the groups you like and the photos you share reflect a professional image that you would want to share with a potential employer.
Facebook and Twitter can give good insight into your daily happenings. If all of your posts and/or tweets highlight your weekend activities, think again about how you use these applications. Remember that Twitter posts come up on internet search results. A good piece of advice, don't post anything online that you wouldn't want to see as the headline of tomorrow's newspaper.