My advertising professor conducts a madatory resume workshop for her students. She has given me some totally awesome tips.
Since you are applying for all kinds of jobs, a summary of skills section could be helpful. Basically you just list what you're good at, also special training like being bilingual,Quark/Photoshop, etc. Especially good if you don't really have job experience in that area and your page is looking blank.
She also conducted research with recruiters, and they said that a call to action is really important if you're using a cover letter. Just add that you will be contacting them in one week to follow up, then do it. It shows initiative.
