I have a bit issues with "look" and "looks" when to use each of them..
- this apartment look/looks gorgeous
- it is look/looks ugly
- those buddies look/looks pretty cool
also please give me as many examples as you can so that I can strengthen my understanding

See a translation

Looks is used just like any other verb in present tense. When the first thing in the sentence, the subject, is singular, so only one thing, and it isn't "you" or "me", you would use "looks". In all other present tense examples, you would use "look":

I look
you look
he looks
she looks
it looks
they look
we look

For your examples,
This apartment looks gorgeous
It looks ugly
Those buddies look pretty cool

A way to help check is if you can replace the first noun/subject with he/she/it, it must use "looks", while if you can replace it with "they", it must be "look"

This apartment looks gorgeous -> It looks gorgeous

Those buddies look pretty cool -> They look pretty cool

So every case that is he/she/it or can be replaced by he/she/it is "looks", and every other time it is "look"