This piece for Malachain collects the advice that holds up in practice.
Open-source software is published with its source code and a licence that lets anyone study, change and share it. Many familiar tools work this way, from web browsers and office suites to the systems that run most web servers. For ordinary users the main benefits are lower cost, long-term availability and the fact that independent experts can inspect how the program works.
Choosing an open-source app is much like choosing any other. Look at how recently it was updated, whether there is clear documentation and whether an active community answers questions. Download it only from the official project site or a trusted app store. If a project you rely on depends on volunteers, reporting bugs clearly or contributing a small donation helps keep it alive.
There is more to learn on this subject, and the linked website goes into greater depth. Treat this article as an introduction rather than the final word, and check any important decision against up-to-date, reliable sources before relying on it.
If you try any of these ideas, start small and adjust them to your own situation. What works for one person will not suit everyone, and it is fine to keep only the parts that help. Writing down what you changed, and what happened, makes it much easier to see after a few weeks whether the effort was worthwhile.
The most useful step is usually the first one. Pick a single suggestion, try it for a couple of weeks, and then decide whether it is worth keeping. Small, steady improvements last longer than ambitious plans that are hard to maintain once everyday life gets busy again.