Thanks for the criticisms. Very helpful. It turns out my email was misdirected, so I've got another chance to edit this. Hurrah.
Regarding my cover lette, you're right, I didn't give any solid evidence of my skills. I thought cover letters were there primarily to entice the reader to read your resume, rather than skip it. I tried to make myself sound interesting and exciting. My resume is where I put the instances of good communication skills (though I may not have made them clear enough).
Regarding my presumptuousness, everything I read online suggested I do that. However, I might change it now that I've given it more thought.
Regarding my lack of details, I figured the first two you question would not need to be fleshed out before I was in an interview. I considered the fact that I excelled the way I did and was offered a management position to be interesting enough to warrant an interview without giving them too much to read (amount I gave them to read was a major concern). My logic was, if I've succeeded at a job that involves certain duties, like setting goals, do I really need to go into those goals, or can people imply that they were done well? I can see how being explicit would give them less to figure out though and help my chances, so I'll do that.
I'll add details to the other ones too.
Thanks a ton.