Has this happened to you? While shopping for plants in the spring, the plant dork in you becomes too loud of a voice to talk down, and you end up with a grouping of wonderful but completely incoherent, plants. This makes for a garden that is interesting when viewed up close, but as soon as you step back, YIKES! You are left with something I like to call a design crime scene. This is why January is a useful time to think about your garden in a more calculated, less impulse-driven manner. The snow in your garden provides a clean slate of possibilities, and the fact that you can't act on any of ephemeral ideas for a few months allows you time to consider your choices more in-depth.
This more intentional way of seeing your garden doesn't need to be a total buzz-kill; you just need to get a few chores out of the way before you start picking plants with wide-eyed abandonment. First, pick a color scheme. You should do this within the context of the larger-specimen plants already established in your garden. Next, think about height and various viewpoints. Decide where you need to bring a bang to your garden. Plan wisely and seek plants that will fulfill your practical needs and your most ambitious garden dreams. If you have a long-established garden, you're probably just looking for annuals, bulbs, and a few perennials to fill things out a bit -- and this is where you get to have some real fun.
Now it's time for the catalogues. Seed catalogs, bulb catalogues, garden-decor catalogues -- bring it on. You have your color needs and your height needs established. As long as you stick somewhat within those parameters, you can let your garden-freak flag fly. Take risks. Get weird. Most importantly, have fun.