Here is the quickest writing exercise I know. It’s a colour walk and it comes from Natalie Goldberg, I think. Though she doesn't tell us to do it over and over...
1. Pick a colour.
2. Go outside for a walk and make a list of every object/thing/bit of text you see that is that colour. (max 20 min)
3. Construct a poem in which you use every single one of the images you've collected on your walk. Don't leave any of them out! Don't take longer than 20 minutes to write your poem. Set a timer and go.
4. Give your poem a title. Your colour ("Pink," "Green," "Blue") could work. Better yet, get all site-specific about it: "Pink Walk in Toronto, May 24, 2017." Sometimes a line of your poem works well as a title. Write the poem first, then pull out a line as your title. When in doubt, use the first line of your poem as your title!
Do this for more than one colour. What do you notice about the difference in mood and tone between your pink poem and your blue one? Is there a difference?
Did yellow make you notice things differently than red? What about purple? Black? Green?
Now, do it all again. Write one poem for every colour of the rainbow. Don't forget black and white. Do one poem a day for a week and see what you find. Make a chapbook out of all your colour poems when you are done. Now you have a book.