Every time I walk outside I try to remember to bring a plastic bag with me so I can pick up whatever piece of trash I see on the ground. It's a bit of a double-edged sword really, while it's nice to take care of the earth around you it's also quite sad to see just how much trash is around you at all times. Thankfully it ends up being nice in the end because I now see less and less litter around on my usual routes. Keeping in mind that some is enough (I don't need to pick up every little piece esp if I'm on my way to someplace like work) and that what's small to you means the world to the plants, insects, and whatever animal that may be in that area does help with this hobby as well
I'm hoping to do more volunteer work and bigger actions for helping the local area at some point in the near future but for now this is a good habit to have