Short preface: this applies literally to everything you would want to attempt, but have a fear to step into it, so the title can as well be perceived as Fear of Start.
Let's imagine the situation. You can only produce paintings and it is the sole activity you would ever pursue. You have just enough money to purchase your necessary minimum art supplies and you buy them, bring them home, and as a next step you need to come up with the most brilliant creative idea that you can sell to make your living. This is the only investment that you could come up with and at the moment your entire wellbeing is tied to the success of what you can put on the canvas... Do you feel some discomfort reading it if you project this situation on yourself? If the answer is yes, think about how probable this situation is (my guess for the group of 1000000 random people ever approaching art would be a half of a person encountering this life-changing struggle for real). Considering that we live in a pool of opportunities for providing ourselves the well-being level we want, it is hardly imaginable that starting a painting (really, insert any relevant project name) can be threatening, however, the subconscious mind triggers the fear by manipulating the feeling of responsibility.
"What if I mess it up?" - what about it, though?! First, what do you define as "mess up"? Only life and death belong to the binary category, while life itself comprises the whole assortment of the options and variations, optimal and less optimal paths. Trying to split the events into the binary system of Right and Wrong is incredibly hard for a human mind operating on a heavily bound multidimensional spectrum of events controlled probabilistically. This means that what you append to the group "Messed up" can happen to be "Well done" elsewhere for somebody else at some point in time, so you can get some reward even for what you initially do not consider to be a good job (Perfectionist Sin). Besides, isn't it a pride speaking from within when you impart such a significance to your future creation?
I am suggesting a set of thoughts that you can develop and interpret in your own way and that can make the creative process fear-free. Most craftsmanship things are already invented, so doing art is mostly to show how you do it your way. We are projecting our unique vision and we are infusing the artistic object (or any other type of product) with our unique footprint and energy. This is the most captivating thing - your personality exhibited such that only you could do it. This is what establishes the bond between you and your audience (customer). If you are in fear to expose yourself at the moment, you likely will try to conceal your character which will produce a work depleted from the personality and breath. The creator needs to be fully open, vulnerable, and comfortable in vulnerability. Knowing that already lowers the potency of the responsibility you put into the act of creation.