difference - You look good vs You are looking good

I have been told that 'you look good' is the perfect compliment to give. Because 'you are looking good' is not colloquial. How correct is it?

For example, if I have to ask others about myself:

1. How do I look?


2. How am I looking? (This would be incorrect I guess)

Having said that, I've come across 'you're looking good / nice' kind of dialogues in English movies.

How to differentiate the uses of both?