I like to give myself a time limit.
Today, I wrote for a cup of tea. When I finished the last sip, I closed Dorico and got busy on another task.
There are all sorts of systems with timers and methodologies, but for me, I’ve found the most effective is something holistic. I know how long it takes me to drink a cup of tea, and that works out well for a writing session. For another project, I might do the length of an album in the background, or until the sun sets, or until the podcast I’m listening to is done, or until the bread comes out of the oven.
Choosing to time my creative work by other things I’m already doing grounds me into the work even as it keeps me from getting lost in it.