The situation is difficult, especially if you are shy and sensitive. Education and character do not allow you to open up and all kinds of hints to the girl why-that persistently do not reach. In this case, it is better to overcome shyness and openly admit his feelings for her. Because any certainty is better than ignorance, and the hints can not get a very long time. Because boys and girls have different perceptions of the same words, behavior. She really may or may not notice or incorrectly interpret the effort of a young man.
If you can't decide, you should resort to the help of common friends. The girl hears something like, "Well, how can you be so blind? After all, he's got a big crush on you, do not notice!", can really see and understand that this young man clearly had stayed in the eternal friends.
The same can be done in a more subtle, veiled form. For example, suppose that the same mutual friend (orfriend) praise you with the girl. Probably will be the same for that. With the indispensable addition of: "Oh, and lucky the girl who's in love with him!"
You can resort to a risky, but effective, way to gain the girl's jealousy. Because a woman understands that she sooner or later it will be necessary to create a family. While the guy (at least, with her) did not show interest in other women, the thought: "And will he be a good husband and father?" could simply not come to mind. As soon as such interest would be shown, she can instinctively rouse: what is this, why would he care about another when I'm around!
Another risky but effective method is to temporarily disappear from the life of a girl. A plausible pretext for this to find easy. She got used to the fact that you are always there for her, you can talk about everything, complain, ask for advice, help. Now let's compare: as has been well with you and as it became uncomfortable, uncomfortable without you.
Well, if the girl is frankly given to understand that you are not her type, what she values you as friend, simply does not perceive as a man – this should be put up. After all, "love can not be"!