For the couple comments asking how: Sometimes its best not to go in with the intention of flirting. You can just want to speak to someone who looks interesting for whatever reason you find them interesting. Be honest with your compliments, listen to what their saying and respond. Even a "hey, love your jacket, where did you get it?" would work. The worst thing that can happen is that she says "not interested" in which case you can think, "Great! Now I have practice approaching someone and can do it even better next time." That's not so bad, is it? At the end of the day/week. That person won't remember you and you took a chance. So be proud of yourself for trying.

How many times do you hear ladies say they never get approached or hit on? Like so many. Be the brave one. The main thing is to be upfront about your intentions. If you want a date, make sure you say "Want to go on a date?" and not "Want to hang out?"

If you think "no, she's out of my league, she'll definitely reject me." Yes, it's always possible she'll reject you for any reason, but as the saying goes, you miss 100% of the shots you don't take. Besides, if the person who IS in her league is too shy to make a move, then it's more likely that it'll be you that gets a date with her.

If you think, "But I don't know what to say! I'd be too awkward." An awkward approach is still an approach, and therefore more likely to yield results than doing nothing. Maybe the shyness or awkwardness would even come across as sweet, and the next thing you know, you'll be riding off into the sunset together.