If you have a volt meter, check your battery and see if you have 12 volts on the battery. If your not getting any lights on the dash or when the door opens and your battery is at 12 volts, you most likely have a bad battery cable. I would replace both the positive and negative cables. this should clear up any problems. now if you have door lights and head lights, but nothing comes on when you turn the key you most likely have a bad ignition switch. Good luck and happy hunting.
First, check your battery terminal connections.
Second, make sure the battery is fully charged and still good.
If all that's good then make sure your vehicle is in Park or Neutral (try both).
If all good still, check your ignition switch.