Courage is resistance to fear, mastery of fear - not absence of fear. So many look to eradicate fear from their lives, when that is an impossible task. You can certainly experience moments in absence of fear, however accept that fear will be with you whenever you are in the process of living creatively. The challenge is to go ahead regardless, simply notice the feeling and manage being courageous.
Keep away from people who try to belittle your ambitions. Small people always do that but the really great make you feel that you too can become great. When you are seeking to bring big plans to fruition it is important with whom you regularly associate. Hang out with friends who are like-minded and who are also designing purpose-filled lives. Similarly be that kind of a friend for your friends.
Sometime, somewhere you take something to be the truth. But if you cling to it too strongly, then even when the truth comes in person and knocks on your door, you will not open it.
All you need in this life is ignorance and confidence; then success is sure. You can "already know for sure" things that could actually impede progress. Always be on the lookout for the things you did not know, that you did not know. Secondly, work on strengthening personal belief that a particular will be achieved regardless of any adversity that may show up, or evidence to the contrary.