A top tool - Word of Mouth
A top way to market your school or church is by Word of Mouth!
Let's keep it simple. From my experience there are a number of classic and contemporary methods to market your school or church. A number of these are free or relatively inexpensive.
The number one reliance is on the most important aspect of marketing - word of mouth. Yes - it's FREE. But does it come at a cost. If good it has usually developed over quite a period of time. If it is bad, it may literally be a few hours / days / weeks old! And worse, it may take years to repair!
Word of Mouth gives authority for the listener. People love stories, especially regarding their child's school or potential school, or how the local church is bringing in the flock.
Work very hard to build and maintain a very good reputation - word of mouth then espouses this...