Mill

• It is most efficient to build Mills next to impassable terrain and other buildings that have empty space requirements.
• Avoid building fields of diagonally parallel mills. It's difficult to place anything productive between them. Lines of houses will not benefit from bank and market and will make troop movement difficult, and farms will have field space wasted.
• Mills are very cheap energy providers with low maintenance costs, but require unreasonable amount of space. Wood shortages are fairly rare, so it's better to eventually switch to Power Plants, and use mills as auxiliary power source whenever an empty spot appears.