It's got to be fun...

This seems almost counterintuitive, but it's vitally important. However you configure the tools in your workflow, it has to be set up in such a way that it is fun. OK, not fun, but it has to keep your interest. If your workflow becomes another boring task, you will stop using it. You may not even notice at first, but you will cease to use it. How do you keep it interesting?
  1. It has to work for your personality type and learning style.
  2. It has to function smoothly.
  3. It needs to be pretty.
  4. It needs to allow for distraction.
Many time-management methods insist that you make your choice and stick with it. This can be counterproductive and lead to disinterest in the workflow. If something is not working, try something else. As you find pieces that work, you'll keep them and continue to work on the portions that don't. While you shouldn't switch tools without evaluating them fully, you also shouldn't stick with something that is causing you to neglect your workflow.
For many of us, this means that our workflow will never be truly set in stone. Don't be afraid of that as long as it is functioning.