Hi Sammy!
As a basic starting point on working with the media, check out the PR section of our Toolkit. There is a lot of great background in there for how the media decide what to cover, etc.
One point you should consider is that the opinions page is the second most-frequently-read page of the newspaper. If you want to write an op/ed piece, first write up some talking points for why you think this should be in the paper (basically a bullet-point summary) and run it past your group of supporters for input. Then call the newspaper (don't email) and ask who is in charge of the opinions page, and tell them you're interested in writing an op/ed piece, and use your bullet points to talk about it. (Before you start your schpiel, though, make sure the person is not on deadline. They'll thank you for it! Also, be concise and to the point, even if they're not on deadline.)
If they say yes, you're golden! Work with your group to write the piece, using your bullet points as a starting point. If they say no, ask if the education reporter might be interested in doing a story on it. And if they say no again, try another media outlet.
In response to your second question, by going to the media, you are taking a risk. Whether the risk pays off depends on your level of preparation, your approach, and, honestly, the personality of your mayor. You might do some research to see how he or she has responded to people criticizing him or her in the press in the past. If his or her response is to ignore the problem or to get angry, this may not be the best approach. But if it's resulted in changes in policy, that bodes well for you!
Hopefully other Forum posters have more tips and ideas for you as well. Good luck!