You are over thinking it. There is a great quote that I can't remember word for word but its something like "You are most creative when you are a child and when you grow older you lose creativity because you try to be CORRECT." That was a horrible interpretation but the quote is basically about how we get older and we don't think creatively because we are afraid of mistakes. As a child you think of absolutely everything! Mistakes are fantastic! You need to stop being uptight with yourself and your abilities and just know that your way of thinking right now is what is setting you back.
Art isn't specific to anything. What is so wrong with creating your vision of detail or your own logic of shadowing? If you can do it in a creative way that makes sense to the whole composition then WHY THE HECK NOT? You don't need to follow any rules. What if you draw a world where shadows point differently than they would in our world? Or hard textures are actually soft in your world.
Drawing exactly how you see it is just one way of creating a visual image. You could always go through stylization and abstraction of the referent object. Another good tip would be using photo or 3D reference. By doing that you can improve a lot on anatomy, colors, texturing and etc. Once that step is cleared you will find it much easier to draw using your mental vision.
Blackrosekane89Featured By OwnerJan 16, 2013Professional General Artist
You don't "have" to draw what you see. It's. Great way to learn, but if you really don't like doing it you don't have to. Forcing yourself to do something you hate will just make you dread doing the thing you enjoy.
Maybe just set aside time for it? Like maybe an hour or two once or twice a week to practice drawing what you see and then spend the rest of your time having fun with art and doing what you like!