After u get to know a girl, try & put her at ease.
Converse with her often so she can get to know u better, give her
good impression by being helpful & considerate.
Get her to do things with u e.g. help her with her work, go watch
movie etc.
Develop a friendship before u disclose your feelings.
By then, she should be aware of your interest.
U also have to watch her body language to see whether she is
attracted to u. Be subtle & not be too overpowering cos u can
scare her away if u come on too strong.