"looks" is almost exclusively used as a verb to describe the action of looking when it is done by a single subject. It can also be used in the same way that the word "appears" is used when it is not describing the action of spontaneous arrival.
e.g. He looks for the ball.
e.g. The ancient building looks better on the inside.
The exception to this rule is when there are multiple appearances or multiple instances of the noun usage of look (used as a synonym for "appearance"). As a general rule, if you could use the word "appearances," you can also use the word "looks."
e.g. Both the red gown paired with the ruby slippers and also the blue dress paired with the sapphire slippers can be worn under this fur coat to create appealing looks.
If only one appearance was described, the usage of the word "look" needs to reference the singularity of its reference. For the same reason that is would be grammatically incorrect to refer to one canine by using the word "dogs," it would be equally incorrect to refer to an outfit as looks, even if a parson is wearing it.
So long as the look is only one look, it is a look, not a looks. So long as the person is a single person, they have a look; they do not have looks unless their appearance changes. This does not include a change in clothes, in that case, you would say that there are multiple looks which a person wears, not that they themselves have multiple looks. The person is their body and their body has one look at any given time so they have one look until their body changes at which point they will have had multiple looks, but they can never have multiple looks at the same time; therefore, "She looks good" does not mean "she has good looks" but rather "The look that she is presently presenting is good." If you mean to say something referencing all of the looks which she has ever had and has the possibility of presenting, you should say, "At any given time, she possesses multiple outfits capable of creating a plethora of appealing looks."
e.g. The blue dress paired with the sapphire slippers can be worn under this fur coat to create an appealing looks.
There is no other way to use this word correctly. Looks and Look are not interchangeable. They are often used this way colloquially to say that someone has a generally pleasurable appearance, but this is technically incorrect. If it is your intent to phrase this sentence correctly, you should use looks.
Another area that people get confused is the list example.
e.g. My dog and I look for the ball.
Compound verb agreement dictates that the verb should agree with the noun which comes before the verb and is nearest to it in the list so you should use look, not looks in the example above.