As you've already noted, unlike in the Romance languages, in English there is only you for second person singular/plural. Therefore to connote respect, you might need to use additional words, while trying not to sound stuffy.
You could address the person by name (Mr./Mrs./Ms. Smith) and use slightly more formal speech.
Hi, Sherri, do you want something to drink?
Hello, Mrs. Smith, would you care for something to drink?
You can refer to a man as Sir, but it's trickier with a woman; many women feel offended (old) if you use Madam (or Ma'am), so you're stuck with Miss. However, if you say "madame" with a French accent, you can probably pull it off.
Politeness is achieved by using softening words such as would you mind and I wonder if..., using the passive voice (instead of saying, You said you would be here at one, you might say, It was agreed that you would be here by one.), using to + verb constructions (Can I take... vs. Might I be able to take... and other such nonsense, which you can find here, here, and here.
Courtesy is international. If you speak courteously in French,
you should have no problem with courtesy in English.
it is unlikely that you will experience any problems with other languages.