Don't Say: "How does it look like?"

I often hear my students ask "How does it look like?" Unfortunately you can't say that in English. Of course I know what they mean, but it doesn't sound natural.
What does it look like? - correct
How does it look? - correct
How does it look like? - incorrect
Both "What does it look like?" and "How does it look?" are correct. However, don't mix the two!
So what's the difference between the two correct versions and when should you use each one?
Example #1:
I got a new haircut.
What does it look like?
It looks like a rat died and was placed on my head.
Example #2:
I got a new haircut.
How does it look?
It looks good.