Let your coworkers know where you plan on taking your career. Ask them questions about how they decided on a major, field of work, or particular job. Your co-workers are a wealth of knowledge just waiting to be tapped into and usually people are happy to help you and share what they have learned.
Say “Thank You”
After you meet someone for coffee, drop him or her a thank you e-mail for taking time out of their busy schedule to meet with you. Include a few points that you really appreciated or found insightful during the conversation, and ask them to let you know if they come along anything opportunities in their professional work that might interest you or if they know of anyone who you could connect with about the topic that you're most passionate about.
It is also a good practice after your internship concludes to write a hand-written thank you to your boss and/or your internship coordinator. Let them know what you have gotten out of your internship and how much it has helped shape your career path or changed your perception of the industry you worked in. This may set you apart from other interns if your employer decides he or she wants to hire an intern and will leave a good impression at the office - always a good thing, especially if you list the company as a reference and they are contacted by your future potential employer inquiring about your work ethic.
Attend Networking Events
Make sure you sign up for different intern networking events that may be provided through your workplace. By meeting fellow interns you can gain access to events they are invited to. Some sites, such as Eventbrite, will notify you of these kinds of occasions in your area. Be on the lookout for opportunities like these to make new connections and find mentors or potential employers.
Ask Coworkers to Connect You With Their Contacts
You can also ask your coworkers if they know of anyone that might be open to meeting you for coffee. They have probably been in the industry for a while and have accumulated a lot of professional contacts from their various jobs. Let your coworkers know what you're passionate about and ask them if they could connect you to anyone who shares those interests and is further along their career path than you. More than likely, they'll be willing to help you out.
For more information about networking, see The Career Center: