1. Launch any app such as Stocks, Weather, etc. that comes pre-installed with your iPhone or iPad.
2. Press and hold the Power (Sleep/Wake) button until you “slide to power off” slider appears on the screen
3. Release the power button and now press and hold the Home button until the “slide to power off” slider goes away.
That’s it. You will notice that it kills the app. You will also notice that the home button is a lot more responsive.
This is quite an old trick to recalibrate the Home button if it becomes unresponsive. It is not clear why this works, and what’s the significance of using a stock app. But it seems to work, and certainly made the Home button on my iPhone 6 Plus more responsive. I haven’t been forced to click multiple times after trying this trick.
This should also work with iPad and iPod touch Home buttons. If your Home button doesn’t work even after trying this trick, then it is quite possible that it is a hardware issue, and you need to get it repaired. Alternatively, you can also use Assistive Touch (Settings > General > Accessibility > Assistive Touch), which enables an on-screen Home button.