Use fresh baking powder or baking soda
Measure flour correctly by spooning and leveling
Do not overmix the batter
Mix wet and dry ingredients just until combined
Use room-temperature ingredients
Preheat the oven fully before baking
Fill muffin cups about two-thirds full
Bake at a high enough temperature for a good rise
Avoid opening the oven door too early
Let muffins rest briefly after baking before removing them from the pan