---> Characters & purpose of the use.

---> Quantity of the part used from original content

(Do you copy all or most of the things from original content? well many people say one or two paragraph is subtle to use but actually it depends on the copyright owner.)

---> You should know the Type of copyrighted work.

(This should be your original thought or it is based on FACTS rather than any other person opinion.)

<This info cannot be treated freely, but holistically.>

Vishal:-)