How can I achieve a smooth finish when making cake icing?

To achieve a smooth finish when making cake icing, it is important to start with a smooth and even layer of icing on the cake. Use a spatula to spread the icing evenly and then use a bench scraper or offset spatula to smooth out any imperfections. You can also try dipping the spatula or scraper in hot water before smoothing the icing for a cleaner finish.