If you can come up with the next big idea almost every day, but in the end, abandon after a week, this post is for you.
Over the past few years, I realised that it's not important how many projects you do. The only thing that matters is the focus.
And with a single project, it's much easier to keep the context. You know when you left off next time you continue working on it.
It's a paradox, but with a single side project, you will have higher chances of success than with juggling few projects at the same time.
Plus, you will have a greater momentum on a single project as all your attention is focused on it. However, you need to maintain this momentum. Ship consistently, ship often, even smallest changes, and get feedback from your users. It's important to start with baby steps, so the momentum feels bigger.
Rough prototype complete? Ship it and tell people. Fixed bugs, ship it and tell everyone about it. If you form a habit of shipping things it will become addictive to ship new code.
It's fine to have new ideas, but if you focus on something else, just write this new idea down and forget about it. If you decide to kill your active side project, you can revisit these ideas. You will have a list of things to choose from, and most likely you will end up combining some of the ideas together.