If you feel like you've been taken advantage of by girls for being nice and doing things for them but they totally ignored you otherwise....then:
Don't do favors for a girl unless you're DATING her already! Or getting sex.
Whatever it is that you want from a relationship with her, don't do anything until the relationship is there first. So for all the complaining nice guys, please stop doing favors for people you barely know or who ignore you! She won't like or want to date/fuck you just because you do stuff for her.