He is not really nice-looking, and yet he has enormous charm. Use a comma before any coordinating conjunction connecting two independent clauses.

Use a comma before and when adding three items or more.

It was raining when I got home last night. * Use past progressive for a longer action that was interrupted by a shorter action in the past.

My father thinks I should stop smoking. * In this sentence, the verb think is a state verb. It is generally not used in the progressive (~ing) tense.

I fell asleep while I was watching TV. *After while use past progressive.

Everyone has seen that movie.

My sister is being annoying today, but usually she is nice. (We use progressive tenses for actions that are temporary)

If we are late, they will be angry. * Being late is a real possibility, so you should use the first conditional.

If I were a child, I would play outside. * Second conditional = If + past tense, subject + would/could/might. The second conditional is used for unreal cases.

I have not eaten anything today.

IBGE, the Brazilian Institute of Geography and Statistics, is an important institution. Don't take for granted that your readers know things.

The teachers* We use "the" when talking about a specific group.