First: Enable Developers OptionsGo to Settings> About Phone > and click on build number seven times. This will enable your device's Developer options, which will give you access to more advanced settings
Second: Switch your runtime from Dalvik to ART
Go to Settings > Developer options > Select runtime > Switch to ART. (Make sure you have more than 50% battery, the switching process take a lot of processing power, you phone will not only suck about 20% of your current battery but it will get really hot)
After rebooting, your device will begin to optimize your apps for the new runtime. This should take a few minutes, but when complete you will notice a considerable performance boost on most devices.
I should warn you, though, that some (and I mean very few) apps may be incompatible with the ART runtime. If one of the apps you use is unable to open or you are having trouble receiving a software update, simply switch back to Dalvik mode using the same process