Most mountains are made of dirt, rock and other materials found in nature. Mountains form when plates of the earth's surface collide. You can build a model of this formation even if you don't have the advantages of nature at work.
Assemble your ingredients. Mountains are made of many things. The basics are dirt, clay and rocks. When you are out gathering your supplies, let your imagination wander. If you see something that would make your mountain look more realistic, add it to your supplies.
Shape wire mesh into a mountain shape. Remember that each mountain is distinct, so whatever shape you imagine is fine. Place your shaped wire onto a base of your choice.
Cover the wire mesh with clay. Make it either smooth or rough and ragged, depending on what you want your mountain to look like. Set it aside and let it dry completely.
Cover your mountain with dirt. If you are having a hard time making the dirt stick to the clay, mix with a bit of water. Pack it in tight to the clay. You can make your mountain smooth or give it lumps and bumps.
Decorate your mountain. Use any greenery you have. Grass and twigs work well. You also can leave your mountain barren. Remember the tree line, where plants stop growing because of altitude.