To speed up your android you have to change your runtime of android.and for that follow the steps.
If you have not unlocked your developer options then follow this steps
Go to your android's settings>About phone and find your build number and tap on that for 5 to 7 time simultaneously until it says that you are a developer now.
Then go back and you will see a new option developer option.Get into that and in that you will see a option android runtime open that and you will see two runtimes DALVIK and ART.
It will be default on DALVIK change it to ART and it will ask you restart your phone hit ok and sit back for 5 to 10 minutes.
There you go.