Flirt a lot, then flirt some more. Humor is sexy, find as many sexual innuendos as possible, talk sexy topics, be sensual, escalate kino! Don't worry about obvious, because it always is obvious .... Duhhh. Just have some light-hearted fun and touch away to see how much she is gonna let you get away. P.S. When two people mutually find themselves sexually attractive- the tension is already there. Kino is probably the most powerful weapon in our arsenal.