Annual flowerbeds give us a "do over" every year. If the marigolds did not do so well last year, we could try petunias or zinnias instead, or if it turned out that bed was shadier than you remembered, try begonias or coleus. You can find just about any color or size of a flowering annual you need.
Perennial beds take a little more time to get them just right. Something out there may be just a little too tall or wide for the space you have, does not bloom when the catalog said it should, or turns out not the color you wanted. Planning now about how you are going to move the plants to another location makes it easier for spring, as you already know what you are going to do. Planning now also allows the gardener to focus on what needs to be ordered, and not get carried away with all the colorful images in the garden catalogs.
While you are looking over the yard, wintertime is a good time to see the potential sun and shade patterns in the landscape. Sun and shade patterns will help guide in the selection of plants and flowers that will thrive and produce the garden we want. When you see the pattern in the winter, think about how much more shade will be in that spot come next summer.
Something else that you can continue to do is add to the compost pile all winter long. You will not have yard waste, yet the raw vegetable kitchen waste along with the spent coffee grounds and eggshells are great candidates. You don't have to make the trip to the compost pile daily, just save up for a few days to make the trek to the compost pile worthwhile. (If you are collecting for more than a week, a trick is to keep it in the unheated garage so things don't get smelly!) Once added to the compost pile, the cold weather will break down the cell walls through freezing and thawing and you will have your winter additions well on their way to being compost come spring. Some other things that can placed in the compost are the spent holiday gift plants like poinsettia, mums, azalea and holiday flower arrangements, after you have removed any floral foam, support wire and any holiday decoration that may have been included with the arrangement.