There are two ways that I know they give results.
One is using Seeder
, an app you can find in XDA that gives you entropy level with a very
little amount of ram consumption.
And the other one is Greenify, it not only help you extend your battery life, but to improve the ram ussage.
(This both requires root acces)
A few tips:
Apps in sd card will run slower depending in the sd class (must be class 6 or superior), other way it will slow down the apps running from there, in comparison with phone storage.
Turn off animations in settings will help a little, but it wont be very noticeable.
Uninstall apps you wont use in months.