I think picking the right idea is the most important thing. A lot of the "never launched" side projects I see were just too big an idea to do as a side project.

I think picking the right idea is the most important thing. A lot of the "never launched" side projects I see were just too big an idea to do as a side project. You need something relatively small, that you can build and launch quickly in a short amount of time. Find a problem that people are willing to pay to have solved, but that is relatively small in terms of time to develop a solution that will solve the problem. You can do this as a side project because there are lots of things that can make a great side project, bring in a few 1000 dollars a month or more, but wouldn't be interesting to someone trying to launch a business they want to scale. Look at tools and plugins for software people use already, especially software that has a reasonable pricetag and that people us in their businesses. Anything you can sell to people for whom time is money is a really good start! I launched a side project 5 and a half years ago which went on to become our entire business. I wrote about that, in a way that I hope will help other people do the same, in my book The Profitable Side Project: http://rachelandrew.co.uk/books/the-profitable-side-project http://rachelandrew.co.uk/books/the-profitable-side-project