It depends on the cause. I would start by restarting (turning off and back on) the tablet regularly. This frees up resources that will only free up when restarted. Also, make sure you close other apps before doing things that take up a lot of resources, like games. So make sure you actually close any apps you were using prior to starting the game.
On top of that, I would suggest you also check your WiFi or data connection (depending on which you are using) to make sure there is no major change in speed. That can lead to freezing as well.