I spoke recently at UCSD on a recruiter panel for engineers and last week I attended a career fair at SDSU. A few weeks ago I was at BYU. So I've spoken with students recently and many of them want internships this coming summer. Following are some ideas that may help:
Have a crisp, clean resume that shows what you're studying, when you plan to graduate, your GPA, previous internships you've had, and that lists extracurricular activities that are potentially relevant to an employer. Give the corporate recruiter everything they need to choose your resume over a huge pile of other resumes. Don't even think about getting fancy with your resume formatting. Make sure that the contact information is accurate and up-to-date. Only list an email address that you check at least daily.
Update your LinkedIn profile to show everything you've done that an employer might want to know. You do have a LinkedIn profile don't you? If not you're missing out on the single best method of connecting with people who work in the organizations you want to intern with. Link to your other online sites such as facebook and twitter. But first make sure there is nothing there that could dissuade a potential employer from hiring you.
By all means apply online for summer internships. Just don't expect that you'll get a call back. Use LinkedIn and all other means available including your parents, family friends, coaches, and anyone who wants to help you make connections. What you're looking for is an introduction to someone who may actually be motivated to assist you. Making those calls and sending those text messages, IMs and emails will separate you from the pack.
Go ahead and attend on-campus career fairs. But have a plan and do some research on the companies you visit. Find out what they do and what sort of people they are hiring for now. Nothing impresses a corporate recruiter more than a well prepared, well presented student with a plan. Think of the few minutes you'll spend at the booth as a mini job interview. Maximize your chance of success by being personable and knowledgeable.
Talk with your professors and ask them if they know any companies that are hiring. Believe it or not organizations do contact your school asking for the names of the top students. Your school wants you to intern and to be successful in finding high paying jobs after graduation. Those are great measures of the value of your program. Schools develop reputations for producing highly qualified graduates who are ready to contribute soon after graduation. Work with your school. They want to help you.
Don't be a butt head. I'm sorry but lots of the students I speak with fit in this category. Not everyone can have a 3.0+ GPA. Not everyone has interned before. Not everyone is studying what is currently hot. Not everyone is comfortable connecting with strangers and asking for something. You're in school learning new things every day. Use those same skills that you are developing in school and apply them to seeking out an internship. Nobody is going to hand you anything on a silver platter. This too is going to require some effort on your part.
Go for it!