This are based on personal experience
U can set up all ua email addresses under the Gmail app instead of having yahoo,outlook mail provider apps independently running in the backgrd hogging down ua ram.
Use ram friendly music player (I realized the newly updated Google music is always running in the backgrnd even if ur not listening to music) freeze/uninstall it.
Its always recommended u restart ua device after heavy usage as some apps might be still running in the background
If possible or rather if available, use WiFi instead phone data,WiFi is more battery friendly than using data...u can use small devices like ideos to create wifi...
Perform a Nandroid backup maybe once in a month to ensure u always have the most current state of ua device,delete the old ones..
Don't drain out ua phones battery to 0% ukiona Imefika maybe 5% just switch it off
Don't run social apps like fb,twitter (they usually go hard on ua ram) instead just use ua browser
Mwenye ako na ujanja zingine aongeze tuelimishane.