Consider where objects are to be placed. Keep your fields together in order to maximize the effectiveness of the rain spell. Less than a one charge is required to water one field, however after you tap and hold the clouds will not stop raining until you release. When fields are spread out, this will result in wasted water. Keep a steady supply of crops. Fields will stop producing crops after twenty harvests. A steady supply of crops us needed to create items that your worshippers want. Reserve an area of your world to grow crops, and make sure there is always something planted. Plants make nice decorations for your worshippers, but plenty of trees will also be needed. They will produce wood needed to answer the prayers of your minions and are required in the construction of new factories.