Most important is to have a well-written and compelling article. Every newspaper has different guidelines for accepting an op-ed. Some accept email, others only faxes. The best way is to call the newspaper up and ask for the op-ed editor and ask what the guidelines are. If you submit your op-ed by email or fax, follow up with a phone call to make sure it was received and to ask when you can expect an answer.
Disappointment is an integral part of trying to get an op-ed printed.
In our experience, MOST of our op-eds are rejected. Do not be discouraged. If your op-ed is rejected by one newspaper, try another. If none of them print it, try again with a different piece another time. If you are only willing to try once or twice, then op-ed writing is not for you.