When I am writing something important, I spend a lot of time trying to figure out how to re-write certain sentences to "sound right" to me. It sure would be easier to if I knew how to pinpoint the problem.
Rewriting is necessary to eliminate wordiness. Reducing a sentence to a verbal phrase is one method of eliminating useless wordage and tightening up your writing. Another practice is to use strong active-voiced verbs, which put 'muscle' into your writing. Interesting and variety of vocabulary is also a must in good writing....and simply by reading widely, one absorbs vocabualry...osmotically, IMO...LOL