If you can only be creative when the mood strikes you, the creativity assigned to you will surely dwindle.
If you can work on-demand
You will always be
See if this helps:
Try setting a timer for 25 minutes
It’s called the Pomodoro Method but don’t look it up – or look it up after your 25 minutes are done
And just start writing.
A little of both
The only rule is:
P.S. If you try this, I’d love to know how it went. Personally, I use it to write these emails