What are gravitational waves relative to? I have been having trouble picturing what kind of waves say Sun and Earth would make. Looking from top perspective Sun is in the middle and denting space while Earth is moving which is also denting space but creating a wave also. However, in reality Sun is orbiting galactic center, galaxy is moving, everything is moving.
So are gravitational waves relative to where we observe them? It doesn't sound right as in water if you were in a boat your boat will still create waves even though it's not moving relative to you. Or imagine two balls in water. One is Earth and one is Sun. Ball A is in the center and ball B is revolving around A.
So ball B does create waves but if you move the whole set of balls, as does our solar system, ball A will create waves as well. 
Is space static medium like water? If so, then it should be possible to figure out Earth's true/absolute motion based on waves that the Earth is creating.
 A: 
so are gravity waves relative to where observe them?

Gravitational waves are  traveling distortions of spacetime at velocity c , mathematically represented by sinusoidal functions and do not depend for existence on the observer. 
The earth, moon and planets have gravitational fields, and these  fields are the ones shown in the two dimensional representations of gravity as membrane distortions. In the center of mass of the sun system, this field is static. As with the electric and magnetic fields, static fields do not emit gravitational waves. In  partial contrast to the electric and magnetic fields, which emit electromagnetic radiation when there are accelerations or decelerations of the motion, gravitational fields have an extra condition: the mass distribution system must be asymmetric. 
Thus the extreme weakness of the gravitational constant and the symmetry requirements reduce the radiation that can be emitted by the earth moon system for example, to very small values. See @tfb 's answer here.

is space static medium like water. if so, then it should be possible to figure out earth's true/absolute motion based on waves earth is creating.

No, space is not like a medium. It can be described by the General Relativity equations and from those wave type space distortions were first predicted and now found.
