off of = off.
Of course, I'm not implying these all must be changed. Remember, you are looking for concise writing, writing that expresses what you want to say in a smooth, flowing manner. This attracts readers. This keeps them interested to read to the last page.
One tip that comes to mind in searching for more exact synonyms is to use the thesaurus feature in Word. It's helped me when I draw a blank on replacements. However, I'm passing along this link which gives 50 wordy expressions with their one word substitutes. Caution: I don't favor all of them. For instance, replacing in order that with so. (refer back to last week's post on passive words.)
So (haha!), there you have it. Go forth and chisel away at those wordy expressions and enjoy your week!