In the body paragraph you will basically express your interest in taking admission. Important things you are going to mention include the basis for applying to the school. Why do you think this school can build up your career? List down all academic achievements and special skills that would help in making your letter stand out from rest of the applicants.
"Letters of intent are often touted as a 'non_legally binding' way to get the parties to set forth in writing what the undertaking is among them relative to a transaction. Too often, parties will sign such a document, feeling that they have little or nothing to lose by doing so... [True, that's] one of the attractive elements of the letter of intent [its purported non_binding nature]. However, courts have found letters of intent to create binding obligations, even if the letter itself does not explicitly state that it is binding... certain provisions within the document may indeed [still] have legal effect."