I have my share of past and ongoing side projects, including hobby websites [1], funny tutorials [2], an ebook [2], coding references [4] and a CSS framework [5].
Like the blog says, the motivation is always here at the start. It’s the second part, when this motivation fades, that is hard. What you need is discipline. I work from home so discipline is key, even in my professional work. How you acquire it is through time management: you need to dedicate time to a project. I do this through predefined 2-hour slots each day or week where I have to work on a project. That way I don’t have an endless timeframe in my kind (because endless would mean “this is never be finished”) and provides me a repeatable and reproducible pattern. And by scheduling it in advance, it provides me with a plan to look forward too, and not end up sitting in front of my computer during a break and asking myself “What should I do now?”.
[2]: https://jgthms.com/web-design-in-4-minutes/
[3]: https://jgthms.com/css-in-44-minutes-ebook/
[5]: https://bulma.io/