Test different materials for their effectiveness as magnetic shields. To do this place two magnets close enough to each other. If the like poles are face-to-face then the magnets will repel each other. Unlike poles attract. Now, place a shielding material between the two. If the material is an effective shield, the two magnets become invisible to each other. Two commonly available materials that work effectively as shields are iron and steel.
Experiment by using different thickness of the shielding material. The science behind this is simple. In electromagnetism, permeability refers to a material's ability to absorb electro-magnetic forces. The greater the permeability, the greater its absorbing capacity, and thus effectiveness as a shield. Find the optimum thickness of material you will use.
Place the shield at various distances from the magnet to find the most effective separation.
Test to ensure the effectiveness of the shield. There are two simple ways to do this. You can use a gauss meter--an instrument used to compare the strength of magnetic fields--or a common compass. Place the compass or gauss meter a set distance from the magnet, and note the result. Now place your shielding material between the magnet and the test instrument. If the shield is effective then the results should be different.