Before you start decorating for Yule, you'll want to get things organized. If you're not organized yet, now's your chance to get there. Each member of the family should be responsible for their own belongings. Sort your belongings so they're in a place you can find them later, in a way that makes sense to you AND your family members.
If your home has a common area like a family room or kitchen that tends to attract clutter, get a basket for each person who lives there. Throw all their stuff in their basket -- the next time they go to their room, they can take all their stuff with them to put it away.
Do you get magazine subscriptions? Newspapers? Create a place that's a permanent home for them -- a basket in the bathroom, a drawer in the kitchen, wherever people read. Then get into the habit of only keeping the last two issues of each. Recycle the old ones as new ones come in.
Remember, the floor is not a storage place. If you can't get something put away, get rid of it.