Break the Year Up By Month
Start with the school calendar to mark out all the performances for the year and any important events and then choose a theme for every month along with a music concept. Hint: Center the theme around whatever is happening in your performance so things will flow easily when you get busy. Examples of themes are space, scary stuff (for October), animals, rainy days, or the seasons. Examples of musical concepts are rhythm, performance, dynamics, or intervals.
Break Up the Month By Week
Use the school calendar to mark off any days off and then create activities for each week. I break my class planning by age. Preschool, K-2, 3-5, Middle School, and High School. Let your fun theme help you find activities. You can create folders or notes to help you brainstorm and find the most engaging activities.
Use the State Standards
Use your music state standards to help complete your lesson planning. Notice I didn't say start out with this? I find it much easier to plug the standards in and use it to polish up anything that I may be missing, than to start with these. I'm sending you a free example of my Music State Standard Checklist for Florida to use as a template and a starting point for your own. Just plug in your own state standards and begin!