The first thing to do is find out what is causing the problem: an app, multiple apps, the system itself? Trepn Profiler by Qualcomm will show you the real-time CPU load for individual cores, an overview of network traffic for both data and Wi-Fi, GPU loads and RAM usage and more.
Free up space: All those photos you've taken and all of those apps you’ve installed can take their toll on your phone. It needs a little breathing room to run smoothly and if it's running low on space, it can start to slow down.
Cut back on the widget: All those widgets you have running on your home screen may be useful, but they also take up their fair share of resources.
Disable unnecessary animations and extra:
Depending on the launcher you are using, you may find that there are various animations and special effects in place. These may look great, but they can also slow things down.
Check in your launcher's settings to see if there is a way to disable any of these unnecessary extras, and you could earn yourself a speed boost.
Close down apps and free up RAM: Multi-tasking several apps makes it easy to switch between different tools, but there can also be an impact on performance. You can quickly close down any apps you are no longer using by calling up the running apps list – press and hold the home key and then swipe away any apps you want to exit.
Restart your device:
A quick and simple fix for a slow device is to simply restart it. This can clear out the cache, stop unnecessary tasks from running, and get things running smoothly again.
Just hold down the power button, select the Restart option, and then tap OK to confirm.
