First off, I use a recipe for sugar cookies called No Fail Sugar Cookie. It is a great recipe that is very tasty and does not expand to much in the oven so your cookies stay true to form. The recipe is below.
No Fail Sugar Cookie
6 cups flour
3 tsp baking powder
1 tsp salt
1 tsp salt
2 cups butter
2 cups sugar
2 eggs
2 tsp vanilla extract (I sometimes use almond extract)
Cream butter and sugar until light and fluffy. Add eggs and vanilla. Mix well. Mix dry ingredients and add a little at a time to butter mixture. Mix until flour is completely incorporated and the dough comes together. Chill for 1 to 2 hours. Roll to desired thickness and cut into desired shapes. Bake on ungreased baking sheet at 350 degrees for 8 to 10 minutes or until just beginning to turn brown around the edges. This recipe can make up to 5-dozen 3” cookies.
I always roll my dough either on a Silplat mat or directly on my granite. It keeps it cool which keeps it firm. Also, I put a piece of wax paper over the dough while I roll it out. If the dough gets to warm it is difficult to work with so only take a little bit out at a time.
Now after they are baked and cooled I begin to ice them. I use a royal icing. It sounds gross but the cookies are super tasty.
Royal Icing
3/4 cups warm water
5 TBSP meringue powder
1 tsp cream of tartar
1 bag powdered sugar (2 lb)
In mixer bowl, pour in the warm water and the meringue powder. Mix it with a whisk by hand until it is frothy and thickened...about 30 seconds. Add the cream of tartar and mix for 30 seconds more. Pour in all the icing sugar at once and place the bowl on the mixer. Using the paddle attachment on the LOWEST speed, mix slowly for a full 10 minutes. Icing will get thick and creamy. Cover the bowl with a dampened tea-towel to prevent crusting and drying. Tint with food colourings or thin the icing with small amounts of warm water to reach the desired consistency.
The icing can also be kept at room temperature in an air-tight container for up to a month. 
I will post some more pictures of other cookies I have done to give more ideas. They are just on another computer and it is very late...or early....depends on how you look at 4:45 am.