oh bother. speaking as a girl, unless she's a flirt, most likely she's dense and hasn't the foggiest that you're interested. it helps if you've got things in common, but you don't want to get yourself stuck in the "just friends" category, so, if you talk about normal stuff, find that you really do like her and decide that you don't want it to be "just friends," i'd start simple, but make it apparant that you've got an interest. like a movie just the two of you. then, at least you know her feelings/reaction sooner rather than later.