If you can deal with it...
every Google atrocity on the device that you can do without should be disabled.
The worst offender is Google Play Services, but many things are tied into that one.
Any apps that you don't use should be uninstalled, or if there are bloatware system apps you don't use they should be disabled.
If you have opened your developers options, you can gain a tiny bit of speed by decreasing or eliminating the circled items below.
Tap each one and select a lower value, or even off.
Also in developers options, you can check your running apps.
This will tell you all apps that are running at the moment.
It can also tell you which app(s) are slowing down the device by using too much memory and/or running constantly.
I have a few more tricks up my sleeves, but try these first.