Here's other quotes and sayings you can motivate yourself with. Practice only makes for improvement.
No one knows what they can do until they try.
Begin to read a book that will help you move toward your dream.
Once you have dared to dream, I believe you MUST pursue that dream. If you do not pursue your dreams they will consume you; the knowledge that you had a dream but did not pursue it is killing knowledge. Consider it absolutely necessary to go after your dreams.
Go after what you want as if your life depended on it. Because it Does!
Review your goals twice every day in order to be focused on achieving them.