Act like you're not interested, but be available.
Tell them how awesome it is :-)
She looks at you and she smiles.
they could tell them they would die with out it because we need most of the stuff it provides
This is perfectly normal. You could tell her
Ask her. She will appreciate your honesty.
if she smiles at you and laughs
No
You just get an odd feeling that you like her.
A girl will always talk about him and stares at him or looking for him
If it's a girl and you are a guy you could give her flowers. Girls like flowers and say "I love you." Or you could just tell the girl that you like her. Or you could ask the person out for dinner.
I do not have a word or a sentence but you could start of by making her laugh and be cocky and after you have her attention,you say that"I have something to tell you".
wait for it to hatch.