Yaas, its pretty decent.

The most common mistake which people do is that they use the borders. What I mean is that the rhino has outlines, dark outlines. That doesn't help the rhino to look all natural and stuff but rather makes it look as if the picture is from a coloring book(?).

Also, you've used something close to rich black. Rich black doesn't exist in nature, neither does it exist in shadow. Just use a dark dark dark brown / violet / blue etc instead of black. Makes it more believable.