If you are using Android phones then comparatively you might have faced the more problems to be slow than other devices.There are some simple ways to make your smart phone faster.
(1) Restart your phone
If your are using your phone for a long time then the processor of your mobile gets tired so it also may be the cause of slow your mobile. So if your mobile got slow then first time switch it off and restart again.
(2) Make sure that your operating system is updated
Operating system is another main cause to be slow your mobile. If your are not using the latest operating system of your mobile then your mobile gets slow. If your are not using the latest version of your operating then update it. To check your version of your operating system go to setting>more>about device>software update> update (check for update). If available update it.
(3) Delete all unwanted apps,musics,videos, pictures
The videos, images,musics,apps you downloaded occupy lost of space in your memory. If memory of your mobile got full then it also may be the cause to be slow your phone so Check your memory and delete all unwanted,useless apps, pictures,songs and videos because phone runs more speed if there is lots of space in your memory.
(4) Clear the cached
When you open an app once some of fixed data saves in your phone that's why you don't have to download it every time you open it. To save the data of your mobile most of the apps automatically save fixed files in your memory, it is said cache. Your phone may gets slow because of this kind of cache so you have to clear it. To clear the cache of your phone go to the setting>more>storage>cached data, click on cached data and clear it.
(5) Watch dog task manager
Every apps you downloaded don't have the same capacity. Some of them uses much resources which causes to be slow to your phone . Download 'Watch Dog Task Manager" app from play store to know which app is using much capacity or space. This app shows details about the used capacity and space of all apps. So according to this details you may delete the apps which use much capacity.