The great majority of your interactions with your iPad come through the use of its touchscreen. App selection, Web scrolling, game inputs and message composition are all possible only if the touchscreen is performing according to expectations. Troubleshooting your iPad touchscreen takes a bit of trial and error, but once you have an idea of the cause, the solution is easier to wrangle.
Restart your iPad to clear out any temporary software glitches or bugs. Press and hold both the Sleep/Wake button and the Home button for ten seconds to force a device shutdown. Press the Sleep/Wake button again to turn the iPad back on; check the touchscreen after the device finishes rebooting.
Clean the iPad screen to remove dust or debris that could be causing touchscreen problems. Power down the tablet and gently wipe the screen with a damp microfiber cloth, then turn the device back on and recheck the screen. Even a small water droplet can interfere with the touchscreen's ability to accurately read touch gestures.
Open the Maps application. Double-tap the center of the map as well as each corner to troubleshoot whether your iPad's touchscreen problems are universal or specific to one area of the screen. This is especially useful if you notice that one application has touch problems in a certain area; testing in Maps will let you know if it is the touchscreen or the app that is experiencing problems.