Scenario: you’re using opensource software and you aren’t donating yet, however you have enough money left over every month to do so. Something(s) is holding you back from donating. Think about what that is and what would have to change for you to change that.
I wouldn’t donate to projects that are already well-funded, or to foundations that spend a lot of money on the support of outside projects (I’d rather fund such projects directly, if I see them worthy).
Overall, I would prioritize small to medium projects that need funding the most. For example, I would donate to Lemmy, but not Mastodon.
Aside from that, I also care about actual openness of the project (i.e. free participation in its improvement), a strong open-source ethos, and independence from corporate backing.