Apartment advertising??!?!?

Their are a lot of huge apartment complexs in my area.Some are spread out, and some are high rises.How do some of you advertise in apartment buildings?? I would often have to sneak in apartment complexs behind and people and such.I would often go room to room sliding flyers under the door.I might add people cursing me out for sliding paper under their door all of the time.I just need some different methods and ideas that you all use?? Thanks for any input I really need it!