Use cake flour instead of all-purpose flour
Measure flour accurately and avoid adding too much
Add sour cream, yogurt, or buttermilk
Use oil or a mix of oil and butter
Add an extra egg yolk
Do not overmix the batter
Do not overbake the cake
Bake at the correct temperature
Use simple syrup to brush layers after baking
Wrap the cake while slightly warm to trap moisture
Store the cake in an airtight container
Add applesauce or mashed banana for extra moisture
Use brown sugar or honey for added moisture retention
Let the cake cool completely before frosting
Frost the cake to help seal in moisture