Oven Temperature

• Baking isn't like cooking - it's about chemistry and you can't wing it. When a cake is inserted into an oven that hasn't been heated to the correct temperature (whether due to human error or an inaccurate thermostat) it can result in an improperly cooked cake. The outside has been cooking longer because it heated up with the oven, and the center remains uncooked.
  
  

Overworked Batter

• The first step in mixing up a cake batter is to cream together butter and sugar. Mix it too much, and you pop all the air bubbles that allow the cake to rise. Same goes for the addition of dry ingredients. You might be tempted to skip sifting the flour, and decide to beat the batter until the lumps disappear -- don't. If the batter can't rise, it won't cook properly and you'll wind up with a depression in the center.
  
  

Improper Measuring

• It can't be said enough -- baking is about chemistry. If you add too much or too little of one ingredient, the batter just doesn't mix properly. Too much fat or sugar can prevent the cake from rising. You should always spoon flour into the measuring cup lightly, then drag a butter knife along the top to level it. Pay attention to any inconsistencies in the positioning of the wrapper when cutting butter from the stick, and always use individual measuring cups rather than a large 2-cup measure.
  
  

Other Considerations

• You may think you've been meticulous, but your cake could still be doomed if you don't pay attention to altitude instructions or pan sizes. Double or triple recipes need to be cooked at a lower temperature for longer, and you may need to adjust your cooking time or temperature if you live in a high-altitude area.