For communicative purposes, rhetoric is an amazing field of study. Many of the texts I used in college were crap, but Jay Heinrich's "Thank You For Arguing" is pretty phenomenal as far as being a quick and accessible primer to rhetorically-charged language.

I'd also suggest a good creative writing course (I'd pick prose over poetry, but they're your classes now); the workshopping process did a lot for me as far as developing a critical eye toward language. One could only hope that it would do the same for you.