Turn the fireplace mantel into a focal point using color. You can hang different-colored stocking or you can display an array of floral ornaments, also featuring a rainbow of colors. You can even borrow a few ornaments from your Christmas tree and display them on the mantel in a creative way. You can use candles to decorate the mantel and make it glow. Use candles of different shapes and sizes and votives and arrange them as you find it fit. You can also use a few other things in between, like pine cones, Christmas tree branches, tree ornaments, etc.
When you first get started on home interior decorating, it is a good idea to have at least some notion of the kind of color scheme you might like. That is not to say that you cant change your mind while you are working out a plan. It is much better to change at this stage than when you already have the paint on the walls.