Make sure that your name is enrolled at a law school before applying at a law firm for internship. This is important because almost all law firms would only consider your internship application if you submit proof of ongoing studies at a law school along with your application.
Write a perfect resume and cover letter. Keep in mind that these two documents create your first impression. Make sure that there are no grammatical or spelling mistakes in the resume and the cover letter.
If you cannot decide an appropriate template, consider browsing the internet or using one of the default templates in Microsoft Office Word. Furthermore, include information about a few of your personal experiences related to the type of law you intend to practice upon becoming a lawyer.
Look for multiple internships which are open for candidates. Your college's career services department or alumni office may have some information for your career. Alternatively, you can contact the United States Department of Justice or personally visit a few law firms to check if they offer internships. Be sure to inquire about the application requirements of all the available internships you find.
Fill out the required application forms; attach the copies of the required documents along with a copy of your resume with a cover letter, and send the complete application to all the law firms that you found in the previous step.
Make sure that your application reaches its destination at least a couple of weeks before the deadline date. This can be ensured by sending the application at least three weeks ahead of the deadline date.
You should hear back from one or more law firms within a few days. However, if you are not contacted by any of the law firms, make a follow up call and inquire about the status of your application.
Keep in mind that it is not binding upon a law firm to give you an internship. That is the reason why you should be persistent but not annoying.