One advantage of winter greens is that they last pretty much until you're sick of them. It's easy, if you do a little planning first, to use your greens for several weeks, and change the flowers as they mature. This means you can create a new look as well. 

So start with the evergreens you like best-- the Pines have such a nice line, and because of their high pitch content, smell good the longest. Cedar has a nice drape-- avoid the incense cedar if anyone in your household has asthma or is pollen sensitive. And Fir fills the spaces well. There are many different evergreens, and most will do well inside-- they're called evergreens, because they don't truly go dormant and lose leaves or needles with changes in weather, so don't limit yourself to the "traditional" ones.

Hydrate in a bucket for a few hours before arranging-- some pitch will bleed into the water, making it grey or yellow. Make sure your chosen container is spotlessly clean. Clear vases will show the ongoing pitch discoloration, so plan on changing the water often. Colored glass will disguise that, but remember for the health of your flowers to change the water! If you are using floral foam, soak according to directions ( yes, there really is a top and bottom). If you are reusing your greens over several weeks, plan on using a new piece of foam for every arrangement. Old foam has holes from old stems-- if you stick a new stem in, and it's not exactly the same length, or goes across an old hole, the space left there will make it harder for the new stem to draw water-- and your flowers won't last as long.

Every time you change the water, you do need to recut the stems so the flowers and foliage will continue to draw water-- so start a little longer than you want the final bouquet to be. With a little practice, you will figure out how long to start. If you have access to evergreens in your yard or that you can gather for free, the possibilities are unlimited.