Expanding Your Comfort Zone
Deliberately move out of your comfort zone from time to time. Even if you feel highly uncomfortable writing music in a different style or for a different line up than what you’re used to, it is a great exercise and will sharpen your skills. If you’re mainly writing for orchestra, why not try writing something for jazz or vocal ensemble? If you feel most comfortable in writing big epic trailer music, why not try writing a romantic love theme?
These pieces should probably not be for a certain project as you might not be statsfied with the first result but ultimately, they will give you a broader “compositional vocabulary” that will be also highly useful in your “daily work”. Challenging oneself as often as possible is a great way to improve as a composer.