direct-opener-getting-alot-of-rejection ... highlight=
^ the post in this thread could be useful for you when considering how to screen
other then that, improve yourself in every way possible, and give an approach some real effort, if a girl is being difficult persist, give it a good 2-3 attempts to get her attention, project your voice, stand up straight, look her in the eye when you speak (if persisting makes you feel uncomfortable then I suggest you take it further and for a few nights practice persisting until absolute concrete rejection from the girl, get her to tell you to go away or fuck off)
if you find just about every girl is ignoring you and giving you negative responses before you even open your mouth, the fist thing to consider is what image are you projecting for a first impression
are you dressed well?, is your hair done?, do you smell nice?, are you healthy (do you take care of your physical fitness)?
if you cant even get your foot in the door and you believe you are projecting an attractive image, chances are, the approach is either extremely weak and you are not putting a real effort into it, or the polar opposite you could be coming off as intimidating and threatening