I have read suggestions to not over mix batter, fold in ingredients, substitute applesauce for oil, and to preheat oven an additional 25 degrees.
Can you share the recipe with us? I'm curious as to what the leavening is, the ratio to the amount of flour, and the acidity of the other ingredients. Also, if you substitute applesauce for oil, your baked goods will be heavy and sticky. Fat helps baked goods rise.
I'm curious about the recipe as well. The amount of leavening concerns me. Applesauce will certainly contribute to heaviness, but it also adds acidity which you would want to balance with some baking soda so that the baking powder can act more effectively.
what is your altitude? I'm a high altitude baker and have started adding a tad more flour to all my recipes not just the ones that offer high altitude measures.