Sounds like a web design course. Without directly answering the questions for you, look at some websites...what makes them cohesive from page to page? How are things grouped together? Read up on Gestalt principles as applied to design. Andy Rutledge has a nice 3-part series on it...here's the third part (you can find links to the previous two at the bottom of the page)
Gestalt Principles of Perception
"Terminat Bora Diem, Terminal Auctor opus."