Adding sour cream or yogurt improves flavor by adding moisture and a mild tang.
To produce a soft crumb and enhance the flavor, use buttermilk instead of regular milk.
For more moisture and a soft, sensitive texture, combine butter and oil.
Mashed bananas, carrots, or grated zucchini provide moisture and a touch of sweetness.
To add moisture and a rich, caramel-like taste, use brown sugar in place of some white sugar.