Luckily, I have a great relationship with my nieces and they know I am passionate about education, 
But I would still make them decide where they want to go eventually. They trust me so much so that I’ve been referred to one of her friends for college selection advice (for free, of course). I think the secret is to make them have the ultimate decision. My role is really just to give them options that meet most (if not all) their requirements/needs, coupled with some strategy, then they make the final decision as to which colleges to put on top of their lists. These students don’t really have the time to research schools because of their overloaded HS coursework (APs, extra curriculars, writing essays, etc) - so my role is to step into the research part for them and filter the vast information that is on the internet! Another reason I am their private counselor is that these students would rather talk to me than to their parents because it’s always better for the student to talk to an objective third party regarding their college applications than their parents who might mostly base their decision on the financials and put less emphasis on value and overall fit.