One decorating habit that I've adopted from my mom is to change my throw pillows with the changing seasons. Since the pillows on our family room couch were very summery, I switched them out with some pillow covers that I found on sale at Pottery Barn that were more neutral and fall-like.
The striped pillows appear to be no longer available on the website but the pillow in the middle can be found here on sale for just $14.99.
The blue button pillows (which I've had for a few years now) are available in other colors here.
I like these ones because they are neutral and can be used in any room and probably during any season.
I've had the same pillows on our living room couch since spring (don't tell my mom) so I'm on the lookout for some new ones for the approaching holiday season.
Here are some that I like from Pottery Barn
(if you click on the pictures, it will bring you directly to their link on the website):