Can you me with this?
try to "get into the head" of a character who works against your protagonist in any novel. then, writing in the first person point of view, compose a piece as if you are this character, and reveal his or her feelings about the protagonist.

First, you have to know about the relationship between the protagonist and the antagonist, or your "evil" in the book. For example, lets take Snow White and the Evil Queen. The Evil Queen poisoned Snow White because her mirror told her that Snow White was the fairest of them all, when the Queen believed SHE was the prettiest. Therefore, the Queen could have felt resentment towards Snow White, or even bitterness or hate. You would then write from their point of view, using their mind set against your protagonist, and create a story to enjoy. Pretty much:
1. Find relationship between characters
2. Relate yourself to them (put yourself in their "shoes")
3. Find their emotions towards the protagonist
4. Write with their mindset in your brain.
Hoped this helped!