Replace water with milk
Use melted butter instead of oil
Add an extra egg
Add an extra egg yolk for richness
Use buttermilk for a tangier, softer cake
Add sour cream or Greek yogurt
Add vanilla extract
Add almond extract for a stronger flavor
Add a pinch of salt
Add instant pudding mix
Add mayonnaise for extra moisture
Use coffee instead of water for chocolate cake
Add cocoa powder to chocolate cake mix
Fold in chocolate chips
Fold in fruit, nuts, or shredded coconut
Brush layers with simple syrup
Frost with homemade frosting
Add zest from lemon or orange
Substitute heavy cream for part of the liquid
Bake in a smaller pan for thicker layers
Do not overmix the batter
Do not overbake the cake