1) what are 2 ways to increase gravity between 2 objects?

The gravitational forces between two objects depend on the

product of their masses, and on the distance between them.

That gives you two distinct ways to increase the gravitational

forces between them:

1). Increase the mass of one or both objects.

2). Decrease the distance between them, i. e. move them closer together.

The strength of the gravitational force between two objects depends on two factors, mass and distance. the force of gravity the masses exert on each other. If one of the masses is doubled, the force of gravity between the objects is doubled. increases, the force of gravity decreases.