Please note that the "How to Rank..." document below does not apply to the current school year choice process. I am unable to provide an up-to-date version for this year.
Instead, here is the simplest statement of how you should rank schools:
The phrase "make your first choice count" is not well defined. Here are a couple examples:
This ranking strategy is based on the fact that all first choice requests are processed first, which means the most popular schools will fill in the first round.
A good way to decide if a school "good enough" is to ask "if I lived in a small town and this were the only school, would I move (or go private)?" If you'd stay, the school is "good enough".
Unfortunately, there is no good way to know which schools are going to be the easiest to get into. You will have to make an assessment of that yourself.