Writing is hard work
Many people I talk to think that writing is a talent. Bestowed to the few and lucky in a virtuous act at birth, or as a reward for some act of random kindness, like saving puppies or nuns from a burning building. Okay, so most people don’t actually think that last part. My point is, that writing is not a talent, although some natural talent usually starts the whole process. Writing is work.
Real, actual, difficult work. If all it took to write a book was a good idea then the shelves would be flooded with beautiful novels. What it takes to write a book is work. The idea is the easy part. The part you love, that you enjoy hatching in your brain for weeks, meeting characters and remarking in how clever you are. Then comes plotting, where you realize you need an actual story line with a beginning, middle, and ending that actually make sense all together. Finally, You come to the hardest part of writing. Sitting down and actually coming up with words on the page.
The difference between someone who always wanted to write a book, and someone who actually does it is just fifteen minutes. The first fifteen minutes you sit down and actually start to type followed by days, weeks, months, and yes, even years of sticking to it and putting more and more fifteen minute sessions in. After all that work you will have a full and complete first draft. Throw it in a drawer for a few months and reintroduce yourself to your friends and family. Then you get to start the editing process.