How we can save energy in buildings?

Actually it is not clear that "what kind of Energy"

anyway here we may consider the 'Electricity'

-Providing required openings on outer surface of the wall that is Windows/Fanlights ect.so that daylight can enter easily inside

-for optomum use of lifts we can provide lift with proper calculation of number of passenger/user

-for multistoried buildings, we may provide overhead water reservoirs in different levels other than providing the reservoir/tanks only on topmost roof

-providing energysaver lamps for lighting in common areas

providing solar panels on roof top for restoring solar energy