When mixing ingredients, be sure to keep mixing the same way each time. If you mix the batter, counter-clockwise and then stop, make sure you continue counter-clockwise when you come back. This helps to eliminate any lumps that may otherwise occur.
Baking is definitely a science. You need to approach it with the utmost care. Follow instructions VERY carefully. If making more or less than the recipe calls for, make sure you convert the measurements appropriately or your baking experiment can go completely haywire. Then you'll have to start over and no body wants that frustration!