It makes me happy to see posts like this. I think just sharing an uplifting attitude and even just a positive personal frame of mind does quite a lot because of ripple effects from that good attitude.

• I think "be a genuine friend" covers a lot of the good in the world.
• take good care of yourself. physically, mentally, spiritually, socially, in all aspects. it means you are less likely to burden others, and it puts you in a better position to be generous and genuinely helpful.
• provide a positive and uplifting environment for people. A lot of people used to get this from Church (at least where I'm from) I think, but a lot of people have decided to no longer do Christianity and have lost that now.
• related: write, produce uplifting content in a way that's easy to access for people who are looking for it.
• be trustworthy.
• use local native plants in your garden
• be strong enough to offer people who need it protection and a way out from those who are trying to hurt them or exploit them or keep them trapped.

I think "average" people may underestimate how much "average" "mundane" good things matter. Sam was the hero of LOTR, and the most important thing he did was just be a good friend. It seems mundane until it's not anymore because you've lost it sacrificing important things to grasp at some goal (the parable of the ring).

Halfway through writing this reply I decided to call a loved one and I had a nice conversation because of this post, OP.