When i asked my girlfriend out, i first made sure she was lesbian/bi. Then i talked to her, got to know her, then said "i think ypur a beautiful girl and i want to be with you"
Unfortunately, there's no easy way. Just ask, tentatively, if she was ever bi-curious. If she says yes, then onwards. But if she said. no, then tell her anyway. She may just be shy! Say, well, would...
If she is always talks about how great you are when you are not around and always seems to be interested in conversation when the topic is about you. that or if they ask you out or is like RACHEL...
1st of all, how do you know she doesnt like you? 2nd...dont just plain out say you like her...let her get to know you...its much easier for her to fall for you if you're funny and fun to be around....