Other than avoiding total discharge of the battery - and correctly maintaining the ipad battery if set-aside for long term storage - the iPad battery requires no additional end-user management to maintain optimum battery health or longevity. More information can be found here:
Batteries - Maximizing Performance - Apple
Your iPad will also suffer no ill effects through being connected to its Power Adapter for extended periods. Your iPad will automatically regulate and optimise charging - and will not overcharge the battery.
When used in kiosk applications - where external power is connected for extended periods of time - the iPad may modify its charging strategy and limit battery charge to ~80% of maximum. This modified charging strategy is designed to reduce chemical ageing that might otherwise occur if 100% charge is maintained at all times.
Nominal 100% charging will be restored when a normal charge/discharge routine is restored.
More information about iPad’s battery management can be found here:
About iPad and iPhone Charge Management Feature – Apple Support