To insure that your people aren't fatigued, build homes in high-traffic areas. Restful villagers are happy disciples. Making a cemetery is another key to villager happiness. If there is a cemetery in the village and someone dies, the villagers will not mourn as long, making them more productive and happier. Another way to avoid mourning is to cast dead villagers out to sea.
Miracles are a good way to quickly meet the needs of many villagers.
In addition, performing spectacular miracles such as lighting bolt, spiritual shields and healing is a good way to convert a large number of villagers at the same time. If you provide a resource they are lacking, such as wood, they will be much more apt to convert to your side as well. To gain more worshippers, you'll have to expand your area of influence. To help you do this, construct buildings on the very edge of your influence. By stretching the boundaries, you can grow the faith and devotion.