If you plan on living at home during the summer, then consider the employers in your geographic area. Students have worked in restaurants, retail stores, summer recreational programs for children, day camps, labs, offices (often as a temp), banks, lawn care, child care, and libraries. Contact these places directly and ask if they hire for the summer and how can you apply. It is likely you will not secure the job prior to summer break, but you can do a lot of advanced leg work to ensure you land a job quickly once you arrive at home.
For more detailed information on applying for restaurant and retail jobs, temporary employment, and summer camp jobs, please see our Summer Internships & Jobs Guide in the right column.
There are many places to look online for summer jobs. If you are open to living elsewhere, there are some good resources for finding summer jobs at camps, resorts, national forests, ranches, amusement parks, etc. listed on the resources section of this page. Many newspaper classified sections start running summer job postings in the spring. It's easy to search most classified sections online. Just do a search for the newspapers in your area, and then look for their summer listings.