Ideal Way Of Addressing Letters In The USA?

Because I do still use US mail. Just recently I had to send something to my financial advisor, for example. In high school, our typing teacher said that there was a way that the United States Post Office preferred to have mail addressed, that was supposed to expedite the processing of your mail.

How did it go (accessing my memory)? Upper righthand quadrant of envelope, all caps, no periods ever. Then city names over a certain length had to be abbreviated. Two-letter state abbreviation, of course, and plus-four zip code, if possible.

Now it's been a while since I've been in HS. So does this format still apply?

Thank you in advance for your helpful replies