Use a multi meter. Put the red lead on the positive terminal on the battery. Then put the black lead somewhere on the frame (If it's a bolt that screws into the frame that would work since everythine else should have paint on them.). If it reads a voltage then your battery and terminals are good.
If the connection is good at the battery. Then check the fusible link, it should connect to the fuse box in the engine bay and is the main power feed for the whole car.