I would send an email to the admissions offices of the schools that you are interested in (or phone call if you prefer), with questions that are thoughtful. Basically, don’t ask questions that you can easily find out from the website. An example might be what sort of culture is there on campus and if there is a lot of collaboration within classes. There are ways to show interest to schools without doing visits. Many top schools also travel to high schools or do info sessions across the country, so you may want to get on the schools’ mailing list so you can figure out when the sessions are.