Fear tells you stories. Fear of action (procrastination), fear of failure (anxiety), fear of success (self-sabotage), they all speak countless lies into your ear, but they have problems keeping their stories straight. Fear will often tell you two lies at once - one vary convincing lie, and another lie, also very convincing, but the exact opposite of what it told you just a minute before. Examples:
"I don't know enough to succeed." / "I don't need to study, I need more natural talent."
"You'll never have enough time to write a book." / "You've got so much time, you can afford to put it off."
"They would be a huge help, but you're not good enough to meet with them." / "You don't need them."
"People with natural talent succeed, not me." / "I can succeed on talent alone, no need to practice."
"If it was really your passion, it wouldn't feel like hard work." / "You only succeed if you suffer a lot."
"They succeeded because they knew someone." / "I know someone, but I can't ask them for help, because _____________."
Yeah, fear will play ping-pong with your mind until you call it out - take note of the false, contradicting messages that you're feeding yourself all the time, and work hard not to give in to the lies.