Everybody loves photos taken with the long time exposure :)
not so long ago I also made few shots like this. compared to yours they were completely lame and without any bigger vision or idea. your post gave me a booster of creativity. photo with red and blue "hurricanes" is my favorite one. below few samples of my last happy shooting session.
I started the same way, just haphazardly waving a flashlight. Later, some ideas began to appear.)) And various devices for color effects.)
I wish you success in creativity.)
Here a lot depends on the background. It is advisable that there are no dynamic objects - napimer as on your photo - a flag. Slightly turn the camera to the right - what would be more of a night city.