Many fall perennials such as asters are past bloom and have dies back at this point. Cut back as foliage dies to keep your garden clean and pest free.
Composting leaves works double duty: it gets rid of fallen leaves and provides a great amendment to future soil. Consider the Brown & Green method. ‘Browns’ are materials high in carbon: leaves, needles, sawdust, and straw. ‘Greens’ are materials rich in nitrogen: kitchen scraps, coffee grounds, and livestock manure. Three parts ‘Brown’ to one part ‘Green’ is the proper compost ratio. Make sure to turn the leaves regularly to increase the speed of composting. The moisture level should be that of a semi-dry sponge.