1 - Delete any apps you never use (i.e. VZ Nav, VVM, BB Maps, etc...)
2 - Close your applications when you're done using them (menu-->close instead of the Esc key)
3 - Battery pull
Just as there are different kinds of apples (Fuji, Red Delicious, Gala,...) there are different kind of memory, some faster than others, some more expensive than others, some more power hungry that others....