I agree with Amanda on plant selection. We have a LOT of oak trees on our property, which means a lot of shade. We've planted literally hundreds of hosta and fern and they are doing well. We have some heuchera and helleborus and are starting to add columbines.
If you have a garden center nearby, check with them on varieties that will do well in your area. Also, for spring color, you can also plant hyacinth, tulips, etc. They'll be winding down their light requirements as the trees are leafing out. For shrubs, you can also use azalea and rhododendron.
By the way, when I say 'garden center', I'm talking about a real nursery, not the local Home Depot or Lowe's. They may carry a lot of plants, but not not necessarily a lot of knowledge about them. (None of the staff at our HDs or Lowes knows anything about what they sell, including when and how to water.)
I don't know what your winters are like, but if you get a lot of snow, now is a good time to prepare that small bed that Amanda mentioned so that it's ready to receive some great plants in the spring.
Here are some shots of our gardens.