I just make subtle changes for fall - chunky throw blankets, natural elements, and vintage books,
Some fun fall throw pillows are always nice to have to add depth and texture to your space
I find that the patinas on vintage items seems to lend itself very well to fall
Natural elements like dried flowers (especially hydrangeas) are perfect for autumn vignettes. You can also never have enough candles in my opinion when the weather starts getting cooler and it gets darker earlier each day.
I've added some faux fall garland to my range hood and a few little terra cotta pumpkins. However nothing says fall like a soup or stew cooking on the stove.
Even my front entryway go a little bit of a fall make-over