It's important to avoid tidying your yard too much, because that destroys habitat for wildlife. Things you can do:
* Are you lazy? Leave it where it falls! Wildlife loves a carefree yard.
* Make a leaf pile, or mulch trees and flowerbeds with leaves. I always get a few wheelbarrows to put over my flowerbeds. This provides insulation as well as wildlife benefits. Fallen leaves have many uses. If you don't have trees, plant comfrey, a miner plant that makes huge leaves you can slash-and-drop several times over the growing season.
* Make a brush pile. Create a log cabin core of bigger branches and then pile twigs on top. This attracts birds and small mammals.
* Make a mulch pile using chips of wood or bark. This mimics a natural forest floor. It also hosts a detritus food web. Mine is 3 days to apex. \o/ If you have big slabs of bark, stack them criss-cross for hibernating insects. I have ladybugs out the wazoo here at Fieldhaven, so whenever I see bark slabs I do this.
* Make a fallen log garden. The bigger the better, but anything thick enough to last a few years will do. Plant some forest wildflowers around it, or ferns -- anything that likes a moist shady spot. A log is a haven for wildlife. You can also stack smaller logs into a pile. Our log pile consists of tree trunk sections that we never got around to splitting all of for firewood before they rotted.
* A patch of bare earth is good for everything from burrowing insects to dustbathing birds. Look for a patch in deep dry shade that doesn't grow much if anything. To make it nice you can put a border of stone or brick, or just leave it as it is. My birds like to dustbathe on the patio, in the firepit, in the driveway, and a few other places.
* Leave the seed heads and pods in your wildflower garden. They provide food and cover for various species. Of course, you can also collect seeds to plant more wildflowers. I can't be arsed to do all the cold storage steps, so I usually just plant them in the ground. Some will get eaten, but that's okay too.