On other occasions when I have had a bad day at work, I'll want to zone out whilst I color; for these times I often find myself reaching for a mandala. There is something about coloring my way through those circles of pattern that really help my mind to switch off!
It took Michelangelo 4 years to finish the Sistine Chapel so give yourself at least a good couple of years of practice to produce your first coloring masterpiece! You need to invest in your coloring hobby to reap the rewards! I don't mean you need to go spend your life savings on the most expensive art supplies or furnish part of your house with an art studio, I mean spend the time to allow yourself to become better at coloring. Most things in life take practice and coloring is no exception.