Staying Organized in High School? Please Answer?

I had a really big desk calendar and hung it on my wall in college I got 5 different colored markers and in the begin of every semester I'd take each syllabus and mark it out on my big calendar. The fact that the calendar was so big made it really easy for me not to miss. Each day I looked at it and saw what I had due. I also carried around a smaller "agenda planner" to write down what was due too in case I forgot to look at my calendar that day. I did pretty well overall so I guess it worked :) Good luck!