Why silly blueberry?
Are you asking how best to make your feelings (either postive or negative) about a person known?
Actions speak louder than words, however, this may be too subtle for some people; so I guess, it depends on your audience? With some people, you can be quite subtle, and they'll get the message, with other's you'll need to be more direct.
For me personally, I really apprecieate just plain simple honesty, and I wish everyone could just be straight up honest with me, and say just what's on their mind. Esp. if a woman doesn't like me, or has no romantic inclinations towards me; I don't mind at all. Just be honest, direct, and polite.
Mind you, I guess there's a million reasons why women are not so inclined to do that with some guys, not least that he may go psyhco on her. So it may not be the best advice.
Jamie.