If the battery is completely drained it may take up to an hour before the iPad responds.
Plug the iPad into the charger that came with the iPad and plug that into a known good wall outlet. Wait one hour. Then, while the iPad is still plugged in reset your iPad. Press and hold the Home and Sleep buttons simultaneously until the Apple logo appears. Let go of the buttons and let the device restart. If the iPad starts up let it continue to charge until the battery is at 100%.
If the iPad does not start Make an appointment at an Apple Store to have your device examined by a technician. Or contact Apple Support.