Help, how do I respectfully ask out this girl?

I need help refining my strategy to ask out this girl. There's a cute girl at my college that I see on campus sometimes. I've talked to her before so she already knows me a little bit and we follow each other on Instagram. She helps run a club but I don't go to it because it doesn't interest me much and because I go to a different club that meets at the same time.

Anyway I was planning on asking her out on a date next time I see her. My plan is to start by making small talk about how she has been, how the club and her studies are going. She got a new haircut recently and posted it on her Instagram so I'll probably compliment her hair. Finally I'll probably say "I think you're really pretty and you seem really cool. I would like to take you out on a date sometime." I think there's something missing though. If I call her pretty and then ask her out I think she might feel that I'm only interested in her for her appearance. Any thoughts or tips?