Why should I start a new paragraph for every speaker?
One of the best things you can do for your reader is to make your writing easy to follow. This is a benefit of starting a new paragraph for each speaker. If you don't employ this method of separation, there's no clear line of division between speakers, meaning that the second speaker could easily be confused with the first one. Example: "The dog ran away," he said. "I don't think he did..." In this example, not beginning a new paragraph with "I don't think he did" makes the situation look as though this "he" is giving two contrasting ideas of dialogue. The reader might catch on to realize that another speaker is giving the contrasting idea, particularly if you label the speaker after the quote, but the time it takes to come to that realization is not needed if the paragraphs are divided with the speakers clearly identified. For the example above: "The dog ran away," he said. "I don't think he did," his friend argued. The reader does not have to eventually infer that the speaker changed, giving an easier read. To allow your reader that easier read then, always change paragraphs between speakers.
Why should I avoid using passive tense?
While passive tense can be useful in certain writing situations, in general, a more actively-paced work will rely on active voice. The primary reason for this is because of the higher number of words that are required to communicate an idea in passive voice because the action is not being performed by the subject of the sentence. Instead of, "Joe played the drums," for instance, the idea would be reversed to make "the drums" the subject ("The drums were played by Joe"). The additional words not only remove the person doing the action from the primary focal point of the sentence, but they also slow down the sentence by stretching it out. For both details, the sentence feels slower and less energetic. That general feeling is why passive voice should be used in limited amounts.
Is a written note verbal communication?
The answer to this question lies within the actual definition of "verbal." Contrary to the typical opinion about the word, it does not simply mean "spoken." Rather, it links to words in general and the expression of specific ideas through those words. For this reason, a written note could easily be labeled as verbal communication, so long as the written details of the note are words.