I like to color code my agenda to keep everything I have going on organized. In my agenda I use brown for appointments and family events. I use red for things regarding my internship, dark blue for volunteering and student government, and orange for things going on with my friends. I use light blue for school events.
At the beginning of the year I give each of my classes a color to write my homework in as well as use for my notes. I write my homework in order by class, or write no homework so when I get home I know what homework I have in each class. I also write down all club meeting information on the bottom line.
Being organized is super important to me, and during the school year my agenda is pretty much the only thing that keeps me sane!