How can we get society to dwell on positive aspects instead of negative aspects, which normally leads to stereotyping?

Society? What about just changing one person at a time, how do you do that?

The question begs for some cognitive processes. What one sees as positive another sees as negative, and vice versa. You have to focus on specifics. What specific aspect are you thinking on? (Ans: none)
And I challenge the assertion sterotyping is the result (normally) of failure to focus on "positive" (whatever that is).
Here is my point, finally. You cannot ever solve societal problems by being vague and indefinite, and making assertions that are without foundation. If you want to solve any societal problem, such as hunger, or housing, disease, etc....you have to start with one success. The societal solution comes from solving it one by one.