why not sit down infront of a fire- or even a candle- write down some of the bad points and cast them into the fire/ light them in the candle and watch them burn. Visualise the smoke as the negativity leaving you but remember the positive that came from them.
Remember your dead relatives while sitting, and remember good and bad parts of the year.
Make your new years resolutions and blow out the candle.
You could set up your altar with general autumn things, red leaves, pinecones etc- if you wanted to.