Professional pastrycooks usually say that "a beautiful cake is already half sold", it is one of the reasons why they do not put a tart on sale without glazing it ("abricoter" in Fench), i.e. coating it with a thick apricot syrup. This glaze gives a glossy finish to the tart (see the photographs below) and also protects it from the air and thus from oxidation and browning.
It's a quite simple technique that you can easily apply to give to your desserts a professional look. This is how you do it.