Smiling and staring

Ok the moment you get a chance when she is looking at you give a little smile just enough to make her know that you are smiling at her (not too much otherwise she'll think your stupid) then give her a gentle stare dont stare her down just a simple cute looking stare and if she smiles back and stares straight back at you, wait a couple seconds if she still looks at you (and maybe if she bites her lip a little bit) slowly move forward and keep looking at her the moment she closes her eyes then move forward a bit more and wallah your lips should meet

If not and she turns away (or walks away) its ok shes either too embarrased or likes to tease you (just a gesture that she likes you back)