How to write a book: a reference guide

(Please bear with me with the typos I'm sure to have - I'm writing this on my phone in a movie theatre during the trailers, and yes, I'm one of those people.) okay, here it goes...
How do you write a book? It seems like something I'm asked quite a bit and something I'm never quite sure how to answer, besides for 'sit at desk and type till hands bleed'.
So then I might answer with something awkward like 'I... Just... Kind of... Did.'
And then they ask, 'But like... /how/? (I'm sorry, my phone does not seem to want me to italicize.) At which point I stare blankly and they respond with 'well I know I wouldn't have the patience'.
Here's the thing - anyone who knows me I have zero patience. None whatsoever. I get restless waiting for tea to heat up in the microwave for a minute. But with writing EOA (and other shelved manuscripts) it never felt like work. I mean it was a lot of work -scratch that - so much work I thought my head was going to explode- but I was in love with the stories I wanted to tell and captivated by the entire process as I learned something new at every stage, whether it was that more than three cups of coffee in an hour is a bad idea or simply learning to experience the joy of getting lost thinking about a new little fragment of purple prose. Of course there were the days where I wanted to tear my hair out from the endless editing or that pesky little friend named writer's block, but I think, for me at least, the desire to tell the story outweighed the frustrations. And I know this sounds strange, but as a writer you develop such an intimate relationship with each character, at least for me, I felt like I owed them their endings (which is also why I am finding it in me to write the rest of the Corpus Chronicles).
Writing a book takes a lot out of you, and it certainly isn't for everyone. If it's something you want to do, and you feel like you can dedicate yourself to it, than go ahead. But if you're not, it is going to be tough to get through the never-ending author process (it does not end with publishing the book - there are endless hours spent marketing and blogging afterwards). Don't try and write a book just because you want to be able to say you did. Do it because there's a story burning inside of you.
Moral: Find something you love - writing is hard work and not nearly as glamorous as people make it out to be.
-Esha