Look at all that great stuff you’ve written – well done, it’s a good, solid document/presentation/email.
Now, what’s the really important stuff? The key point(s) that you really need the other person to understand?
Got them? Good.
Now, throw away what’s left: all the pleasantries, associated information and other thoughts – the gumph.
Keep control of the piece; the key points are all you need. You should be polite of course, but don’t waste people’s time with information they don’t want; you can be sure that they’re going to scan through (or tune out) until they get to the good stuff, in order to get back to what they were doing before. They’re busy people, after all – chop chop, people to see, things to do. Is this attitude annoying or inconsiderate? It’s both, but it’s how people are, and that’s something you can’t control.
Keep their attention – keep it simple.