Perhaps the best book ever written on how to write clear, concise, and gramatically correct prose is Elements of Style, by William Strunk and E.B White (and no, I'm not trying to talk Ebonics). The book is only 85 pages or so and covers just about everything you just said and a little bit more. A copy sits behind my desk and I assign it as mandatory reading to all new employees.
I have been told, write as you speak.
But, if you talk funny to begin with, the trouble is never finished.
As a ramdon observation of the above, have you noticed how non-primary English speakers tend to write, say, in email or the like?
I agree. I haven't been without a copy since high school. It is appropriately concise; it wouldn't do to ramble on for hundreds of pages while extolling the virtues of simplicity, directness, and brevity.
Another book which should be mandatory (whether in school or in the workplace) is the similarly brief How to Lie With Statistics, by Darrell Huff, ©1954. I consider it almost a companion volume to Strunk and White.
Either book can easily be read in an evening -- and they should be.