There are so many ways to make sure your cake turns out moist and decadent every time! Here are a few quick tips:
Use cake flour. If you can use cake flour instead of all-purpose flour, it usually adds moisture.
Add sour cream. A tablespoon or two goes a long way. Add sour cream to your homemade batter or use it to moisten up a box mix.
Brush with simple syrup. Coat your cake with a light layer of simple syrup for a spongy result.
Don't overheat. Bake your cakes at a lower temperature and don't leave them in the oven for too long.
Don't overmix. Likewise, don't mix your batter for too long. Keep the mixture light and fluffy for a nice and moist cake.
Once your baked cake layers come out of the oven, invert onto baking rack and leave the pan over the cake until the cake cools down. Your cake will maintain better moisture and quality will improve.