So I have once or twice fallen down one of those Internet holes of watching people decorate cookies for hours on end. Through several of these experiences I have realized a new pet peeve (as if I needed another): cookies that don't hold their shape. Like these people go through such great lengths to decorate these cookies, but the cookie itself has lost it's original intended shape. Sure, it's harmless really: but if the cookie's shape looks slightly melty that is like nails on a chalkboard to me. So for your good and mine, I'm going to tell you how I keep the edges of my cookies crisp, and overall perfectly shaped!
My first word of advice to you would to find a good butter/shortbread cookie recipe, as opposed to a sugar cookie recipe. Sugar cookies more often than not include a learning agent of some sort, but this will make your cookie rise, puff, and loose some of it's shape. And while that's delicious: it is not quite as pretty. And if you are reading this, I take it you are looking for the perfect mix of deliciousness and pristine appearance for your cookie. And for that a butter cookie is the way to go.
Once your butter cookie dough is done, do a little test: roll a little ball with it. If it sticks to your hand, add another 3 to 4 tablespoons of flour to your dough. Having a stronger dough will result in a prettier cut-out cookie: keep your eyes on the prize.
Now most recipes will tell you to refrigerate your dough, then roll it out, cut out your cookies, then bake them. But, once you have man handled your dough that much it has more than likely gotten close to room temperature again, which will result in the butter in the cookie melting too quickly and stealing that perfect shape you desire. Instead, after you make your dough roll it out, cut out your cookies, lay the cookies out flat on parchment or wax paper on top of a flat surface, then stick them in the freezer for an hour. Once your cookies are hard as rocks, then they are ready to hit the oven. Since the butter inside the cookie is cold, the cookies will hold their shape better- the same reasoning behind using cold butter when making pie crust.
These are a few of the steps I follow when making my decorated cookies, and they have proven to be extremely effective at meeting my sky-high expectations for the cut-out cookies coming out of my oven. If you have any other questions or comments please leave them down below!