Well according to the formula :
Fg = G • m1 • m2
__________
r^2
If one were to increase the masses of the objects it will have a direct impact on the gravitational force as well, as it increase the gravitational force. It is directly proportional to mass.
Distance on the other hand is inversely proportional to the gravitational force, basically increasing the distance between two objects of substantial mass causes a decrease of attraction or gravitational force between those 2 bodies of mass.