Do you know how to use the meter properly? If there's a lot of snow in the frame, and you use any of the automatic modes, the camera is going to want to underexpose unless you tell it otherwise. If you're using Av or Tv, give it maybe +1EC if there's a lot of snow.
Remember, when left to its own devices, the camera wants to make everything average; it wants the scene to average out to gray. When it sees a lot of snow, it thinks "Wow, look at all that white, better make it all gray" and it'll underexpose. You WANT the snow to be white, right? By giving it some added EC, you're telling it "Yes, this scene is going to be a lot brighter than average."
Now, as far as inspiration, I just went to Google Images and punched in "snow portrait" and got a lot of good hits.
For all portraiture, make sure to pay attention to the background, as much as the subject. If your background is full of clutter, if there's a trash can and a bicycle and a telephone wire all back there, they're going to distract from the subject. Move the subject and move yourself to get those things out of the field of view, or hide them behind the subject. Sometimes you just have to move a few inches to lose clutter out the edge of the frame. Here's a great thread on it: