The best way to prepare for EQAO is through loads and loads of practice. It's my opinion that by starting on the first day of school, students are exceptionally well prepared come May and the language of the booklets is fully ingrained in their schema. We do a little more intense preparation beginning in week 25 but there is no "mad cramming" required since it's just not needed.
Scroll about halfway down to the section called, "Student Assessment and Scoring Guides" and you'll find links to copies of booklets used in previous years. You can print these out and have your child practice their skills at home. These are the ones we use in class to help us to be so successful year after year.