AI am new at cake decorating. I know that my cakes are to be somewhat dence, but my cakes turn out as heavy as cornbread. What am I doing wrong?

what does your recipe and mixing method look like? include how long in the oven at what temp 

My cornbread is as light and soft as my cakes.  backwards maybe.

What are you baking, what type of cake, what recipe?  There are so many people here who could guide you.

AIt really depends on your cake recipe, cooking time, methods of mixing etc. For example, a pound cake is traditionally dense, esp if it's from scratch. However, without further details from you, it's difficult to offer assistance.