Among the proven techniques for improving test scores is regular exposure to skills that will be required for those tests. Daily exposure to language skills -- including skills of spelling, capitalization, punctuation, and grammar -- will build students' skills and increase test scores.
Here's an useful chart that summarises, very simply, how to use 15 punctuation marks, ordered by difficulty. This was created by Curtis Newbold who runs a blog called The Visual Communication Guy. Nice work, sir. Download the hi-res version here.