What are ways that one can increase or decrease the gravitational force between two objects?

To decrease the force of gravitation, one may move in one of either vertical directions from the earth's surface. Gravity is less below and above the surface of earth. F(gravitation) = G0m1m2/r2, where m2 is the mass of the object in question. Therefore as r increases, Fg decreases, and as m1 decreases as you go deeper into the earth, so does Fg