I think you need to take some time to observe carefully. Its one of the most common areas that is overlooked when drawing. We all draw the 5 year old version of what is in our head instead of what we actually see.
Start out with just an eye for instance in the wolf and REALLY look at it. Notice the different values that it has, the shapes, where one section intersects with another, if there are negative spaces that you can use to your advantage. Drawing well is more about observation than drawing.
Start slow, practice constantly and you'll get to where you want to be in no time!
I did a
workshop here drawing animals in coloured pencil. It may help you to work through the exercises, even if you're using graphite.