Are you using the charger it came with? A common thing that happens is that people try to use iPhone level chargers for the iPad. The iPads need more power than iPhone chargers put out.
Have you tried to give your device a reset? Hold down the sleep and home keys, past when you see the red power down slider and until you see the silver apple. Let it reboot and try again.
Are you able to swap out the charger, cord and outlet? If the problem replicates then it rules those out.