So I was thinking of telling a girl she's beautiful, but the more I think about it, the more elaborate use of words I come up with. I was planning to say, '...hey, you have such good face structure, how come you're not a model or something!'...Which could potentially backfire, because she isn't a model (not that I know of), would it come off wrong? What is a good way of telling a girl, without being completely obvious, or is being obvious my goal here?
Being obvious is the goal.
Wait until she's in a good mood, and talking about something, preferably something personal, and interrupt her and say "You're beautiful"
That way, she'll think you were talking about her looks and what she was saying. Women LOVE it when men listen to them.
Just tell her she is beautiful spontaneously while you are with her. Just come out and say "You look beautiful today". And John is right you want to be obvious.
I think walking up to her, looking her in the eyes and just saying "hey, you're beautiful" is best. Simple is good. If you think too much about it and try too hard to be clever, she'll know. I think the goal here is to be obvious, but most of all, be confident and comfortable when you do it.
"You're beautiful," by itself, sounds insincere to me -- not like something you'd say because you were struck by her beauty, but because you thought you needed to say it.
Being specific should do it. "Your hair looks so nice"; "I like your eyes"; "I love the way your smile looks." Of course, stay away from the personal bits!
I agree with Will, probably the best way to say a girl is beautiful is by saying that you like her smile, she'll notice that you aren't just a guy who's after her for her looks, but more a guy who likes to see/make her smile, girls love guys who make 'em smile.
Women WANT a man to be physically attracted to their looks. They WANT to be seen as physically beautiful, AND liked for other reasons, but you most definitely want to let it be known you are physically attracted, then that you are attracted to her personality and intellect, NOT vice versa, Vice versa gets you friendship, not relationship.
You don't want to communicate "I love you for your mind, and in addition to that I find you attractive", you want to communicate "Wow, you're beautiful, and that makes me want to chase you, and I'm liking what I'm finding out about you, too!"
I'm going to come out of left field here and say don't do it, unless you're in a relationship (which doesn't sound like the case here).
If she really is beautiful, she's heard it a million times. I repeat, she's heard it a million times. Probably a few times a week from random, creepy guys. If not told directly, then implied.
But, if your mind is set, tell her in an un-obvious, almost passive, way.
For example: she meets you for dinner and its obvious she is dolled up more than usual. When you first see her, give her a little longer eye contact (while smiling, of course) and when she asks what you're smiling at (she'll of course know exactly what you're thinking, and I bet she'll even start smiling herself) start saying something, then say "ah... nothing" (while still smiling and looking away). Of course she'll say "what, what?", then you say something like, "...you just look great". Man, that sounds corny as hell, but it'll do the trick and sound more sincere than just telling her "gosh, you sure are beautiful".
One extra note: there are a lot of posts like this, do us a favor and post back with your results, no matter what you did!
This, just don't do it.
In fact, if your intention is to date her, to set yourself apart, find something about her that isn't perfect, that she might be a bit worried about.
I remember with one girl, she was rather pretty, but she had little ears that stuck out weirdly.
So, me being me, I would go up to her and just stare at her ears. She was so used to people commenting on her pretty, she didn't know what to do. Flat out told her that her ears stuck out and were rather small. She was beyond shocked!!!! Then give a coy little smile, and say, I love that, got a fetish for such a thing, and just walked off. Teased her off and on, looking at the ears, smiling. Guess who went home with her.
Everyone always tells the pretty girls that they are pretty. If you want to date them, don't be like everyone else, don't feed their ego, feed their desire for a guy that sees everythign else about them.
Coincidentally, she does have a similar feature :)