I interpreted Xant's advice as "generally being a nice guy" which absolutely did not work for me ever. Subtlety sounds more promising, especially compared to try-harding.
There's being a nice guy and "being a nice guy." Being nice while being calm, confident, funny and a bit detached absolutely "works." I say "works" because it's kind of gay if it's just some sort of a girl-hunting tactic, just like if you're pretending to be "alpha." How most people seem to understand "try to be a nice guy" is "being a doormat", desperately vying for attention by buying drinks, etc. That's not the same at all. The difference is in being classy.