Have you read the book ‘The 4-hour work week’ by Timothy Ferris?
I read it a few years ago thinking that it would help me to run my business more efficiently in just 4 hours a week. Whilst it does have lots of efficiency tips for any business, it was built around the idea of building a business purely to earn money to finance a lifestyle. While this may be your objective too I was disappointed that there was no thought of creating enjoyable work or focus on serving a client’s needs.
If you haven’t read the book then I can recommend it as it certainly gave me a few ideas that helped me to run a business I loved in a 25-hour work week, and I believe we helped our clients and their businesses too.
https://amzn.to/2Pa5yrC