Stained Glass Cookies – another approach, what’s it gonna hurt?:
Bake cutout cookies with holes in center 2 minutes less than usual and on aluminum foil. Remove from oven and fill cutout with coarsely crushed hard candies, return to oven for 2 minutes, just long enough for candy to melt. Cool completely on the foil.

Sugared:
Brush thinned icing onto cookies using an artist’s brush. Use one or several colors to paint. Using thicker icing, pipe designs onto wet iced cookies. While all icings are still wet, springle generously with white fine sanding sugar.  Let dry.

High Dimension:
Brush thinned icing on to cooled cookies. Use more than one color of icing to highlight details. While wet, press a smaller cookie onto larger one and ice it. Or sprinkle with crushed candy, nonpareils or decorating sugar. Or use dragees. Let dry. Pipe thicker icing onto edges. Sprinkle with sugar or not. Let dry.

Making Life Easier
To decorate, use lines, not flooding, for ease – outline clothes, emulate yarn hair, squiggle and dot patterns for aprons and buttons, different-size dots for pompoms, hands, eyes, noses, etc.  You can use white icing for eyes/nose/mouth on gingerbread, and probably chocolate for same on sugars.

Or, use flooding technique and then top with candy Xmas trees or red hots. Or, just use solid colors.  Just a green Christmas tree. No decorations on it.

Give reindeer center belts and chocolate eyes and noses. Very minimal.

Make Hanukkah cookies by piping designs on to round cookies – menorah can be done as a line drawing.

Decorating Tools:
Use tweezers to place dragees or candies.
Fluted pastry wheel to cut scalloped edges or geometric shapes out of cookie dough.
Decorator bags – disposable probably is better – and a round tip, star tip and leaf tip.
Broad brush for egg wash, small brush for frosting or luster detailing.

Snowflakes
Base flood coat with light blue. Immediately sprinkle blue sugar. Let dry. Use thick white icing with star tip to pipe swirls and shells along the edges and the center.

Base flood coat with light purple. Using thinned white icing, pipe simple lines into the purple.  Using a toothpick, pull through white icing to swirl or extend and create a marbling effect, away from or toward center.  Let dry.  Pipe tiny white dots around edge.

Base flood coat with light purple and let dry completely. Outline in thick white icing.  Pipe in diamond outlines in two shades of purple darker than base coat. Sprinkle colored sugar inside diamonds. Let dry completely.  Pipe white dots on diamond points.

Base flood coat in white. Let dry completely. Pipe in light purple hearts in center and on tips. Pipe S shapes and dots in dark purple.