Newton's law
Gravity as a universal attractive force acting between all matter.
Force between point masses
where G is the gravitational constant. 
Remember that gravitational force is one of the four fundamental forces.
It is only an attractive force.
Acts between masses.
Is an inverse square relationship 
Gravitational potential
Understanding of the definition of gravitational potential, including zero value at infinity, and of gravitational potential difference.
Work done in moving mass m given by
Magnitude of V in a radial field given by:
Graphical representations of variations of g and V with r.
V related to g by:

Gravitational potential is energy...
Remember that measurements are from the centres of mass  strictly speaking the masses should be point masses.

Orbits of planets and satellites
Orbital period and speed related to radius of circular orbit.
Energy considerations for an orbiting satellite.
Significance of a geosynchronous orbit. 
You do not need Kepler's Laws  but they are good for your soul... 