my instructor tells the white belts to look over to their right, where all the higher ranks are lined up. he then tells them that anyone wearing a belt higher than they are, therefore knows more than they do. they should feel free to ask if they want to know anything. when I was a lower ranking student, I was ALWAYS bugging the higher ranks to show me a technique I didn't know or help me out with my kata. they were always more than happy to help, and now that I'm one of the higher ranking students, I help anyone who asks. However, you have to ask. People aren't going to know that you want to learn something more unless you tell them so. I'd suggest asking a higher rank in your school to show you something you want to learn. Ask your instructor for permission first if you think that might be an issue.
best of luck.
best of luck.