I was trying to bake a normal map to give detail to a figure, and recently I got so frustrated I started working on a test file, to see if it was me doing it wrong. Sure enough, it was.
Steps I took to bake:
Create a cube.
Subdivide it flat 5 times.
Deselect all vertices and select random vertices with select >>> random and scale it out.
Repeat step 3 3-5 times.
5 Duplicate the cube and move it over.
To the second one, add a decimate modifier with unsubdivide mode on level 2. Hit Apply.
Unwrap the decimate cube with smart UV project.
Create a new image on the smart UV project. Keep the default settings and apply.
Select the first cube and then the second.
Under the bake tab in the camera panel in properties, select normals for the mode, and check selected to active. Set the margin to 0 and hit bake.