I'm a software engineer and the author of four books, but none are about software. (Three are pop-sci and one is pop-stats.)
First book (2013) did extremely well and continues to sell well. Lots of good press, translated into multiple languages, excerpts in a national magazine, promotion on a network TV show. Second book (2014) tanked hard. Third book (2019) looked like it would suffer the same fate as the second, but sales have been slowly inching up. Fourth book (2020) has seen abysmal sales, likely because of the pandemic, but it's a direct sequel to the first book and there are opportunities for cross-promotion, so I'm hoping sales eventually pick up.
I've been fortunate that throughout the course of writing these books, I've had a full-time job that pays the bills, so any advances or royalties have been gravy.
But if I could give advice to those who are interested in writing a book, it would be this:
* Unless this is purely a vanity project, do not go in the red. I would not have written my books if I hadn't gotten book deals. I wouldn't have put myself in the red by hiring an editor, a proofreader, an illustrator, a designer, a publicist, etc., which is what you likely will have to do to produce a quality book when self-publishing. A "you have to spend money to earn money" mindset is not the best mindset to have in a category where relatively few books succeed.
* Publishers these days aren't looking for good writers or great writers. They're looking for marketable books in established categories written by half-decent writers with solid platforms. There are certainly exceptions to that, but you can't hurt your chances by strengthening your platform or doing your own market research before even approaching an agent. (By platform I mean a built-in audience -- people to whom you can market the book. For better or worse, this means having lots of newsletter subscribers, YouTube subscribers, a big social media presence, blog readers, etc.)
* If you are an introvert, you will likely find being an author uncomfortable. You might have no problem with the often solitary task of writing the book. But the hardest part (and potentially the most time-consuming part) of being an author is not the writing itself but the marketing and promotion that comes afterward. Don't expect to be able to lean on your publisher for this. After a brief promotional blitz around pub day, you're likely on your own.
* There is a quote attributed to a number of famous writers: "I hate writing, but I love having written." I can all but assure you that if you're working on a book of any decent length or depth, you will reach an "I hate this" moment. But once the book is published, for the rest of your life you get to say that you're an author. It's a pretty cool feeling.
When publishers consider book proposals, they're always thinking about how easy and how expensive it will be to market the book to people.
Paid advertising is effective, but extremely expensive.
Getting press coverage is great, and less expensive than advertising, but you've got to pay a publicist who knows what they're doing, and even then, there are no guarantees.
But if an author has a strong platform, such as an email newsletter with tens of thousands of subscribers, or a popular website or YouTube channel with tons of views, then it's an incredibly effective and inexpensive way to market the book. The author has already established an audience who has shown interest in their previous content, so chances are good that they will show interest in the book as well.
Not the OP but they want authors with big social followings or email lists etc, because the main risk of a book is will it sell - and if you already have a big audience to market to, that risk goes down a lot.
First book (2013) did extremely well and continues to sell well. Lots of good press, translated into multiple languages, excerpts in a national magazine, promotion on a network TV show. Second book (2014) tanked hard. Third book (2019) looked like it would suffer the same fate as the second, but sales have been slowly inching up. Fourth book (2020) has seen abysmal sales, likely because of the pandemic, but it's a direct sequel to the first book and there are opportunities for cross-promotion, so I'm hoping sales eventually pick up.
I've been fortunate that throughout the course of writing these books, I've had a full-time job that pays the bills, so any advances or royalties have been gravy.
But if I could give advice to those who are interested in writing a book, it would be this:
* Unless this is purely a vanity project, do not go in the red. I would not have written my books if I hadn't gotten book deals. I wouldn't have put myself in the red by hiring an editor, a proofreader, an illustrator, a designer, a publicist, etc., which is what you likely will have to do to produce a quality book when self-publishing. A "you have to spend money to earn money" mindset is not the best mindset to have in a category where relatively few books succeed.
* Publishers these days aren't looking for good writers or great writers. They're looking for marketable books in established categories written by half-decent writers with solid platforms. There are certainly exceptions to that, but you can't hurt your chances by strengthening your platform or doing your own market research before even approaching an agent. (By platform I mean a built-in audience -- people to whom you can market the book. For better or worse, this means having lots of newsletter subscribers, YouTube subscribers, a big social media presence, blog readers, etc.)
* If you are an introvert, you will likely find being an author uncomfortable. You might have no problem with the often solitary task of writing the book. But the hardest part (and potentially the most time-consuming part) of being an author is not the writing itself but the marketing and promotion that comes afterward. Don't expect to be able to lean on your publisher for this. After a brief promotional blitz around pub day, you're likely on your own.
* There is a quote attributed to a number of famous writers: "I hate writing, but I love having written." I can all but assure you that if you're working on a book of any decent length or depth, you will reach an "I hate this" moment. But once the book is published, for the rest of your life you get to say that you're an author. It's a pretty cool feeling.