Baking Normals in 2.78

Hi, I can’t seem to create a normal map of an object I am working on. It comes out in one color. How can I fix it?
No multires, I just want a normal map of my existing model

What renderer ?
Do you have both high and low poly objects
Have you enabled ‘selected to active’ in the bake options
Have you set the low poly object to be the active object

ALWAYS supply a demo blend file for review. Save it so all we have to do is press the Bake button