• Frosting: Frosting should be at room temperature. If it’s too cold or coming straight from the fridge, beat it in a stand mixer using the paddle attachment to warm it up a bit.
• Royal Icing: This mix of whipped egg whites and sugar sets relatively quickly. If it starts to firm up before you’re ready to use it, transfer it to a bowl and give it a good stir.
• Melted Chocolate: If melted chocolate is too warm, the chocolate will be loose and difficult to control during piping. If it’s too hard, you’ll have to use too much force, and the resulting letters won’t look natural. So find a temperature that works with your speed and experience. You can also massage the chocolate lightly to make sure that it's all the same temperature once you put it in the bag. (We also recommend melting chocolate in the microwave. To learn why, watch the video below.)

• Piping Bag: If you’re using a decorating tip, consider the surface area of the baked good. If it’s a large cake, you can use a wider tip. If it’s a small cookie, choose a narrower one.
• Zipper-Lock Bag: A zipper-lock bag is a fine stand-in for a pastry bag. Load the bag with icing, pushing it to one corner of the bag. Make a very small snip in the corner—you can always make the cut larger if necessary.
• No matter which piping method you use, don’t fill the bag more than halfway, to give yourself more control. (Check out this quick tutorial for more tips on filling and preventing leaks.)

• Start with Cooled Cookies or Cake: Icing will liquefy and fail to set if it’s piped onto warm cookies. Let the cookies cool completely on a wire rack.
• Decide on Your Font: Will you do cursive or block letters? Keep in mind that there’s less starting and stopping with cursive, but that also means once you start writing, you shouldn’t stop.
• Remove Air Bubbles: Before piping, press out a small amount of filling on parchment paper or another surface to eliminate air bubbles that can cause the filling to spurt unevenly.
• Do a Test Run: How you practice is going to be how you play, so practice on parchment before you start decorating in earnest. Trace the cookie or measure the diameter of the cake on the parchment so that you’re working within the proper space constraints. Or if you’re decorating a cake and have the same-size cake pan, you can practice piping your message on the back of it to get an idea of spacing.
• Hold the Tip at 90 Degrees and About ½ Inch Above the Surface: Softly resting your other hand closer to the tip and using it as a guide, hold the tip at a 90-degree angle about ½ inch above the cookie or cake and gently squeeze to pipe. Any closer and you might ding the surface; any farther away and it’s tough to control where the frosting lands.
• Use Even, Steady Pressure: This will result in a consistent stream of frosting.
• Ensure Even Spacing: You don’t want your baked good declaring, "M   E   R  R Y X MAS" or "H  A  P  P  Y V A L E N T I N ESDAY." Start more to the left than you think you should—it’s easier to add a little bit more space between letters than it is to squish them together if you run out of room. You can always add a flourish or a heart to fill in extra space at the end.

Lead photo: Westend61 / Getty Images

Want to make and decorate your own cakes and cookies? Find hundreds of impressive recipes and useful tips in our cookbooks The Perfect Cookie and The Perfect Cake and in these articles:

• How to Assemble and Frost a Layer Cake
• 5 Simple Cake-Decorating Ideas
• All About Different Types of Frosting, from Buttercream to Ganache