Why not start off small, you don't have to dive in....

one day in passing simply smile and say hi, or good morning, afternoon......

keep smiling.....in passing.....

maybe another day do the same except say "hey, how are you?" and see what happens...

dont force anything....

i bet just after a week of you intiating a smile and hello she'll intiate the next time.....acknowleding your presence....

then offer a simple compliment......

its the small things....