Suggestion: find something else about this woman that you're interested in, something related to her interests - books she likes to read, music or movies she likes... that kind of thing. And then approach her with a comment about that, as opposed to commenting on her physical appearance. Speaking for myself and most women I know, we'll respond much more favorably to a guy who pays attention to something we're interested in and maybe shares that interest, as opposed to a guy who's just paying attention to our physical appearance. Again, speaking personally and based on comments I've heard from other women, if a guy approaches us who we've never talked to or interacted with before and immediately comments on our physical appearance, we tend to find that kind of creepy. Which is why it's better to focus on an interest that has nothing to do with physical appearance.

...That said, it can be hard to discover those things about someone without talking with them first. Unless you see them sitting with a book in public or overhear some music they're listening to, and approach them to ask about the book/music, or have read it yourself and can offer a comment like, "I really enjoy that author," "I really enjoyed that book," or "what are you listening to?" or "I really love that song," it can be tough to find another way to break the ice. Which is when you resort to a simple, open comment that doesn't focus on her physical appearance, but lets her know you're interested and you'd like to get to know her better. Meaning, the next time you see her, approach her and say, "I really liked talking with you the last time we met. I'd like to talk some more. Would you like to get coffee with me sometime?" Again, you're not commenting on anything physical about her, but letting her know you're interested and asking if she'd like to interact with you in a more personal, one-on-one setting. It's a simple comment/question, but can be one of the most difficult things to do, to approach someone and be that open. Just remind yourself, the worst thing that could happen is she could say no. Nothing more serious than that. Yeah, getting rejected is hurtful, but you can get over it. It doesn't have to define your life. You'll meet someone else later who may spark your interest and have an opportunity to try again with that person. Life goes on. Try some scary stuff, see how it goes and maybe you'll find some success. Maybe not right away, but eventually. And I think you're strong enough to handle that.

Good Luck...

Look at it this way, if she's introverted, she may be thinking of you the same way... Someone has to say, "care to join me for a cup of coffee?"

Nothing wrong with being an introvert. It doesn't mean we're anti-social, just that we need to be more mindful about how and where we expend our energy. I feel risk putting myself out there, so I get it. All you can do is your best.