This will be a copy of the comment I made on “write a book”, but it still applies:

It took up well over 6 intense months of research and writing almost to exclusion of everything else, but holding this book in my hands and seeing it on shelves is so great. While I know it’s not going to be a classic by any means, and if it sells a few thousand copies I’m very lucky—but it’s mine, and I did it.

Here’s more about my experience, on my blog.