Take projects that are almost a no-brainer for you to do. Something that you could do within a week or even a weekend. I do sophisticated backend systems as a day job. I have the choice to do it on the side too, but that would mean taking a significant amount of my free time. Rather, on the side, whenever there's an opportunity, I make simple, not transactional (info) websites. It does not pay that much but if you have these kinds of projects every week, it will add up to something.