Prune & Plant
Depending on what kind of garden you have, you should consider pruning and planning as well. Yes, there are many plants that you need to prune during fall. Sage, thyme, or rhubarb, for example, will benefit a lot from autumn pruning.
Also, you can begin planting bulbs for next spring. If you plant them early enough, they will have plenty of time to establish in the soil before the freezing, winter weather, and this will also offer you a head start in the spring.