The textbook I assign for my scriptwriting class has a great inspirational sort of mantra that I've always found to be true. In the book, it is attributed to Goethe - but this article explains the actual source. Where it came from doesn't really matter. The important thing is to read it and see if it helps inspire you to commit yourself to your dreams and endeavors. I hope it does.
"Until one is committed, there is hesitancy, the chance to draw back, always ineffectiveness. Concerning all acts of initiative (and creation), there is one elementary truth the ignorance of which kills countless ideas and splendid plans: that the moment one definitely commits oneself, the providence moves too. A whole stream of events issues from the decision, raising in one's favor all manner of unforeseen incidents, meetings and material assistance, which no man could have dreamt would have come his way. I learned a deep respect for one of Goethe's couplets:
Whatever you can do or dream you can, begin it.
Boldness has genius, power and magic in it!"
- W.H. Murray