Your NCOER is probably the single most important document you'll encounter in your military career. That single sheet of paper affects your chances for promotion, your assignment options, training opportunities, and your entire future in the Army. No other document has as much effect on your career or your life.
The good thing is that the content of your NCOER is in your hands. It's as if your supervisor gave you a blank check and said, fill it in with whatever amount you want. Because you can determine what is written in your evaluation! Your actions and the information you provide with make your supervisors job easier and your report the best it can be. Make sure you give it the attention it deserves.