Make an official campus visit
The student should make an official campus visit through the admissions office. Just walking around campus on your own does not tell the school that you were there. As an alternative, you could attend a college fair or talk with an admissions officer that visits the high school. Make sure you fill out your information so it can be logged in your admissions file.
Students who apply early (through an Early Action or Early Decision program) may have a higher chance of acceptance, because it shows they are thinking about that college before the regular, final deadline.
Exchange personal letters and emails
If you have the opportunity, send a thank you note to the admissions counselor who gave you a campus tour or who spoke with you at the college fair. That personal contact will go a long way toward showing that you want to attend that school.
Each college has its own criteria for admissions, and some weigh demonstrated interest more than others do. Students should find the college that is the best fit and, when they find that college, students should show that they are genuinely interested in attending. This will likely come naturally for students; if they anticipate attending a school, they will want to apply early, visit campus, and communicate with officials at that school.