There are thousands of students who graduate every year and aspire to become teachers but due to limited opportunities and different hiring patterns, it becomes more demanding. Your cover letter for teaching job should be able to hit the desk of the school administration at the time along with other applicants so that it gets counted.
First of all, you need to make sure your cover letter reaches to the right person with correct spelling and correct use of grammar. With the mailbox/desk of the concerned person in the school gets filled with applications, your letter will get only few seconds to be read by them, so it becomes very important to make it look like a "must read" cover letter. If you apply some powerful formatting and writing tricks, it will surely get the deserved attention of the prospective employer.
Please remember that the principal/authority of the school will not get impressed by just seeing your Teaching Cover Letter and start thinking how smart and nice person you are, that deserves this job. You need to be precise and confident while writing the cover letter. Don't feel shy in writing and urging the prospective employer to call you at the contact number you have provided so that you can share your enthusiasm in education with him in-person.
The last thing while making a cover letter which has the potential to land an interview call is no use of easily available templates on the Internet or books. Those letter formats are old fashioned as well as widely used by many. The administrator, who opens or reads the cover letters for initial scrutiny may straightaway reject the same if he finds that the same was not your original creation.
So please make sure that yours is an original and catchier in comparison to others and the person gets impressed the moment he opens your Teaching Cover Letter and keeps it aside, to be reviewed later for final proceeding.