The friendzone is something that a lot of men complain about but seem to not acknowledge that it stems from things they do wrong themselves. Friendzoned men are too little of a challenge, they wear their hearts on their sleeves, they deify the girl with whom they are in love and she can sense that and thus she knows you're someone to whom she can look for emotional support, or in other words - a friend.
However, you are more self-reflective than a lot of guys in the friendzone, and know that it's your own behaviour that's causing you to be friendzoned, but you are now asking yourself, what's the best way to leave the friend-zone? Well, I am here to tell you that it's jealousy. Nothing stokes the flames of attraction in a woman than jealousy. Nothing makes a girl more attracted to you than when she can see that other girls are getting more air-time than her, and that's something that players/assholes/douchbags and me know. They and I know how to play the jealousy game on women, and it works.
How do you make a girl jealous? Well, it's simple. You flirt with other women. However, you have to do it in the right way if you want to escape the friendzone. If you do it in a way that appears to be obvious that you're only doing it to "get back at her" then she'll sense you're butthurt, and game's off. You have to do it unapologetically, and inconspicuously. At first, it'll annoy her (make her jealous) completely because for as long as she has known, her lapdog (i.e. you) has been completely, utterly and so humbly dedicated to her, and that cannot happen! She'll protest at you. You just brush her off as being "creepy" and "needy". This'll annoy her (make her jealous) further.
After all this, you've flipped the script completely. No longer are you the chasee but rather the chased. She will pursue you in order to get more. However, at this point, the worst thing that you can do is fall back into your "friendzone" character. Be flirtatious. Be a challenge. Tease her. Make fun of her.
Other men would argue that seeing that you're getting success with other women, why worry about her? To which I would respond:
Whether women like to admit it or not, they know jealously is one of the best ways to get them attracted to you.