So you can sign the sheets when a school visits your school or region. They do look at those. You can sign in when you do a tour or visit a department. You can email your AO and or professor and ask intelligent questions that can’t be answered on their website. You can look at the college course offerings or clubs /activities and mention that in your essay “when emailing with professor x I learned about x and that is what I want in my college education” etc.
Use words like when “researching x”
Apply Early if you can.
These are all things that show interest.