You may show the level and intensity of your love in a variety of ways. However, always be sincere while demonstrating your interest.
The ultimate way to tell a college you are amongst the most interested of all applicants is to apply Early Decision. Because ED is binding, this option is not well-suited to every candidate. Some students (and their parents) may want to see multiple financial aid awards and merit-based scholarships. Others just aren’t 100% certain and need more time to make a final decision.
Other forms of demonstrated interest include: scheduling a visit, accepting an interview if offered by the admissions staff either on campus or through alumni admissions representatives, meeting with a professor to learn more about your intended major or attending a campus event such as a musical performance or athletic competition.
Remember: Showing sincere interest benefits both you and the colleges. The latter use this tool to enroll a specific target number of students. Admissions Directors want to admit students who truly want to attend.
On a silly note: Will wearing collegiate colors or the mascot make a difference on my campus visit?