As the title says, take your time to give your terrain piece that extra weathered look wether from dust, rust, stains, oil, dirt, flaking paint, moss, algae or blood splatter (the list is not exhaustive).

The entry should be judged after how well it executes one or more particular weathering techniques, ass well as the overall design, modeling and paint job. Remember, there is no way to overdo weathering.

As criteria it can be applied to all types of terrain – just pick a kind of weathering that fits to the material in question.