- Build what you're interested in, not what other people on the social feeds are doing.
- Things that were built for fun can end up making money. So why not aim to build for fun first!
- Build pointless things! (like this). They're great to express yourself and they're much easier to finish and release (less pressure).
- You don't need to finish anything!! But if you really want to finish that side-project, try a pointless project to boost your morale.
- Divide and conquer - Large side-projects can be overwhelming. Divide that MMO game into smaller projects which are easier to finish.
Maybe this is all pretty evident to most people... but it doesn't hurt to see it written explicitly.