You can write a software book and make over 100k $
Here's what worked for me:
1. I started a blog first. This allows you to practice your writing and build an audience.
2. I self-published my book because publishers only wanted to give me just 10% from the profit.
I used @leanpub to write and sell the book while I was still writing it and @teachable to sell it when it was done.
Leanpub gives you 80% royalties. Teachable gives you around 95%.
3. As a non-native English speaker, I used @Grammarly to correct my English spelling mistakes. I'm a huge fan of Grammarly and been their customer ever since.
4. I love diagrams. I use yEd to draw them and @intellijidea for class diagrams. I use Inkscape to change svg diagrams and export them to PNG. I use FileOptimizer to reduce image size.
5. Writing the book took me almost a year of part-time writing. Writing is a very time-consuming process, so don't rush.
6. Marketing is extremely important. I've been using my blog to advertise my book. I don't use external ad services, like Google Ads, Facebook, etc.
7. For the paperback, I used CresteSpace. Now, it's called Amazon KDP. For paperback, images are 300 PPI, for ebook 150 PPI, to save space.
8. By the time you finish a book, you have enough material to create a training or a video course. I did both. Sometimes, I get to fo a training because someone liked the book. Some people buy both the book and the video course, so it's worth having both
9. Don't be afraid to set a higher price if you provide a high-quality book. My ebook costs 25$ and the paperback 45$.
People judge products by price. A lower price might lead people into thinking that the product is low-quality.
10. Don't underestimate the power of discounts. Black Friday really works.
11. Testimonials are very important. You should ask your readers to provide you a testimonial.