1. Oven Temperature- Check how accurate your oven temperature is. Make sure you have an oven thermometer to test your oven for accuracy.
2.Underbaking - Oven temperature too low and/or too short a baking time.
3.Opening the oven door- Don't open the oven door during the baking process. Only open the oven door if absolutely needed, one-half to three-quarter's way through baking.
4. Don't over mix the cake batter - Too much air will be incorporated into the batter. You should fold the flour in to add air and to retain any that is there already. If you beat the mixture instead of folding it, you are beating the air out of it, and that would mean it would not rise as much. Depending on the recipe, if you fold in egg whites, if not beaten fully or folded in too harshly, the cake could fall. In addition be careful not to cream the butter and sugar too much or too little because this can cause problems.
5. Don't over or under measure liquid or under measure flour.