I often get hung up trying to and forgetting how to, stay motivated. There's something to be said for just getting up to sped and staying there. However it's the getting going and knowing what to do when you're stalled that's the hard part. I credit improv for keeping me on my toes and yoga for keeping me flexible but jump starting the mind requires the right kind of exercise.
Brainstorming can be a great way to get out of a funk. Take 5-10 minutes. Choose a word or phrase that you would like to use as a foundation that you'll want to build on and then write down whatever comes to mind. Don't edit your self. Just accept that you mind needs to vent and you don't want to hold back. It's a great way to clean house and also find ideas that may not have occured to you in oth forums
Another tool is memorizing insprirational sayings.
Robert McKee's book Story has a quote that always pushes me back into action.
"We often put off doing something for as long as possible, then as we finally make a decision and step into the action, we're surprised by its relative ease. We're left to wonder why we dreaded doing it until we realize that most of life's actions are within our reach, but decisions take will power."
It's the little things in life that help and reminders and inspirational words can work wonders for the stalled creative mind.