"The greatest mistake we make is living in constant fear that we'll make one." John Maxwell

I have found that successful people are not afraid of mistakes. They take the situation at hand, delve into finding as many options to solve the situation and take the best course of action available at the time. If it is a mistake then they learn from it and fix it. They move on to the next problem area and keep attacking the problems until they are solved. Don't look back and beat yourself up on what you should have done but learn from it so you don't repeat the same mistake.
Thomas Edison made more mistakes in creating the light bulb but used the experiences to get the light bulb.
Keep on plugging away and you will get there.