Try the following tips regularly to maintain optimum performance in your game. Some of these steps may also help with refreshing your game and clearing various glitches.
Close all unnecessary applications
Force-close all unnecessary applications running in the background. Your device usually leaves all apps running unless you manually shut them down. This is bad for overall performance, as the system gets taxed and slows down.
Apps such as Facebook & Messenger may continue using memory even after they have been closed in the multitasking menu.
To check for this on iOS, go to the Background App Refresh section of your device settings, then toggle OFF apps such as these to prevent them from using additional memory while you play. On Android, you can choose "Restrict background data" on each app's settings.
Restart your device
Reboot your device by turning it off for a few seconds and then powering it back on again. This can help to clear the memory of your device from any tasks that should no longer be using resources.
On iOS devices, you may also need to perform a hard reboot. To do this, hold down the power and home buttons simultaneously until the screen turns off and the Apple icon appears. Once you release the buttons your device will reboot.
Try a different network connection
If downloads are progressing slowly or your game is showing messages indicating you’re in Offline mode (in a place you should be able to get online), you may need to try a different network connection.
If you're on 3G/4G, try using a Wi-Fi connection instead; or, if you're already on Wi-Fi, try connecting through a different Wi-Fi network.
Re-install the app
If the app is crashing consistently on a certain level or upon launching, it's very likely that some of the assets you downloaded when you were installing or updating weren't downloaded correctly. Uninstalling the game and re-installing it will usually fix these types of crashes.
On Android, some devices may take a while to fully erase the game files before you begin re-installing. If you have an application manager on your device, try using it to make sure that all of the game files have been completely removed prior to re-installing the game. Restarting your device can also ensure that the memory has cleared these files.
You will want to make sure that you are using a stable Wi-Fi connection to download the game again. Some games can have relatively large downloads, so doing this will minimize the chance of experiencing connection issues which may corrupt game data as it's being downloaded. If you're using Android, the game will need to remain open while installing or launching it for the first time; it may not install correctly while running in the background.
Remember that by connecting though Facebook, Game Center, or Google Play from the in-game settings menu, you can uninstall and re-install without losing your progress; uninstalling an app will usually erase your local save data along with the app. You will want to make sure that your latest progress is available to be recovered after your re-installation, if possible.
Clear some additional storage space
Erasing some photos, videos, or other apps that you no longer need in order to clear some additional space on your device can vastly improve overall performance. It's recommended to keep at least 10% of your device's storage free to prevent performance issues.
Turn off the Auto-Update feature
Downloading apps in the background while you play may cause some evident performance issues such as lagging or freezing during gameplay. We recommend ensuring that your auto-update feature is turned off (particularly using iOS 7). Any apps that routinely require Internet access to download or sync additional data while running in the background (such as Mail apps) are recommended to be closed completely to prevent this process from occurring during gameplay as well.
Close the game completely when you're not playing
If your game is left running in the background, your game's progress can be affected by other occurrences, such as crashes caused by other apps. When you're done playing for the time being, you may wish to take the precaution of fully exiting and force-closing the game.