A. Clare Beckwith says: Look at the trees at this time of year and you will see them change from green to yellow and red and then to brown. Rosy red apples are ripening on the trees, orange pumpkins are fit to burst and golden corn is being harvested from the fields, I can't think of a better time of year to take your inspiration from nature.
It's such a vibrant season that you might want to choose a combination of complementary colours, or even contrasting ones. Pick one or two main hues, and then use a couple of accents to add interest, perhaps for the ribbons on your bouquet. Popular autumnal colours include red, burgundy, orange, peach, rust, gold, mustard yellow, dark green, and brown. Create a mood board by cutting out pictures from magazines and using colour swatches to see what colour combinations work best for you.
That said, if you really are a fuchsia pink kind of girl and want to add turquoise accents, don't let the season stop you. It's your wedding and you should have it just the way you want.