Research the application requirements of each school you'll be applying to. Requirements will vary per school, so don't assume that what's right for one will be accepted at another. You may have to submit slides of your work or the original pieces, digital portfolios, and pieces no larger than a particular size.
Meet with a college counselor to discuss specifications regarding your art portfolio. You can even ask them to take a look at some of your pieces. They may provide feedback or criticism, and help you to put together your final portfolio when you're ready to apply to the school.
Choose ten pieces that reflect your range of work and your talent. You'll want to showcase both technical expertise and creativity.
Include the title, size, date and medium of each piece of work along with the submission.