verbs always match nouns in number, and they usually come before the noun." In other words, make your best guess for the grammar rule that makes sense out of the pattern(s) you see in the phrases you have been working with
Most of the time grammar comes after 'common sense" which is inevitable. Grammar rules don't matter anymore when it comes to informal conversation. We only pinpoint grammar errors when we don't understand the statement. So the easiest way to know if the sentence makes sense is to check if in all time subject agrees to its predicate or supporting details.