Please do not pick up spanish spelling mistakes from your (the rest of your) columbian friends. If the person is already doing it I'd say "Can you not pick up spanish spelling mistakes from your columbian friends?" but "can you not" is a slang usually used by the female community. Or I'd say, "Please, stop picking up spanish spelling mistakes from your columbian friends."

It's fine apart from the 'the'. You would say either: 'Please don't pick up Spanish spelling mistakes from your other Colombian friends.' or, for example: 'Please don't pick up the Spanish spelling mistakes which your other Colombian friends make.' In the first one, 'Spanish spelling mistakes' is undefined, so you have no article - you're not specifying what mistakes these are. In the second, you are defining the mistakes ( the ones which your Colombian friends make) so you need to have the definite article. In fact, the sense is the same, but the grammar is different. And I do sympathise with you about the fact that most of the world doesn't even make the effort to notice what your country is called. It's pure anglophone ignorance, I'm afraid.

It's sound OK to me. However, you don't need to add a comma in this sentence.