As I'm walking around the campus and approaching girls wearing something unusual (so I can make one, two assumptions for stacking) I also see a lot of beautiful girls, but for example wearing casual jeans trousers and white t-shirt.

This gives me a very hard time trying to come up with something to say after I open and I miss many opportunities that way.

What are your observations about that subject? I'd really like to stack better, so I can approach more frequently.