Clear out your RAM to speed up your iPhone:
Even iPhones slow down sometimes, no matter how good iOS is at managing background processes. This tends to happen especially when you’ve done something resource-intensive like playing a few games or clicking dozens of photos.
This is a neat little trick to try the next time your iPhone feels sluggish. Unlock your iPhone and hold down the Sleep button until the Slide to Power Off slider shows up. Then, press the Home button continuously for about 5 seconds till the home screen reappears. Your iPhone should feel good as new since this action clears up all your RAM.
The process is a bit more complicated for the iPhone X since it doesn’t have a Home button. To get over this hurdle, go to Settings > General > Accessibility > AssistiveTouch and toggle on AssistiveTouch. A white and gray circle will appear. Tapping on it will open up the AssistiveTouch menu, with a virtual home button at the bottom.
Proceed to Settings > General, scroll to the bottom, and tap Shut Down. The same Slide to Power Off screen appears, only here you’ll have to long-press the virtual home button. Apply pressure until your iPhone X turns black, flashes white, and then goes back to the Settings menu.