Always let your cakes cool to room temperature or cooler before attempting to frost your cake. Cakes can be made the day before frosting and serving. Your frosting should be soft but not melty. It should hold its shape when applied. Smooth it out using a cake scraper or icing spatula and let it chill in the refrigerator for the crumb coat set. Chill at least 30 minutes before applying the final layer of frosting. You can frost a cake a day before serving. Just keep it refrigerated.