It's part of the human condition to be afraid of change and to feel paralyzed by irrational fears. Remind yourself that everyone is fighting their own fears and looking for ways to turn frustration, fear and self doubt into opportunity.
I'm sure there are people in your life who regale you with tales about someone else who is already doing what you would like to do or having a similar idea and succeeding beyond your wildest dreams. Do not pay attention! Put blinders on when it comes to comparing yourself to anyone else and stay focused on your own goals. The more you think about everyone else the less time you spend thinking about your dreams. On the other hand...
If you do hear about other people's success stories don't get intimidated. Think, "if they can do it why can't I " instead of "I could never do that." You can achieve anything you want to if you put your mind to it and think positively. When one of my patients wanted to go into the jewelry business he started comparing his designs to well established jewelers. So I asked him what made them so special? He had to admit that his designs were just as good, if not better. What they did have that he did not was a lot of drive and determination. Anything is possible if you believe in yourself.
Speaking about believing in yourself -- that's the most important ingredient for moving ahead. You must believe in yourself and act confident and assured. The operative word here is "act." If you don't feel it -- fake it. Think of anyone you know who appears confident and adopt their persona while you push forward. No one will know the difference.
Finally, a helpful trick to do in bed, just before you fall asleep. Tell yourself to dream ideas or solutions which you've been trying to figure out. Then write down your dreams in the morning. This works. There have been many famous people who figured things out in their dreams.
Now, go out there and dream big!