Hanging wreaths on a door is one way to decorate, and these wreaths come in different sizes. Wreaths also have the option of being garnished with lights or ribbon. Another idea is wrapping a front door entirely in wrapping paper and taping it from the inside. Ribbons and other festivities add a unique touch to the wrapped door.
San Francisco Gate mentions adding more decorations to wallpaper doors. For instance, if the wrapping paper has a snowy theme, then adding a snowman figure in the middle of the door is another creative touch.
Hanging brown wrapping paper and applying candy shapes and gingerbread men is way of attaining a gingerbread theme. For a Santa's entrance theme, lining red and white pole stripes along the door is one option. Hanging a Santa's workshop sign on the door is something else to consider. Further addition of elf cut-outs on windows makes it appear as though Santa's helpers are working in a home.
Turning an old picture frame into a holiday decoration as an alternative, instead of using wreaths. Ribbons and other adornments further decorates the frame. Hanging snowflakes on the door to pull off a holiday effect. Hanging a simple garland also suffices as a traditional form of holiday decor. Also lining Christmas lights around a door as another idea.