Good question.
I've taken on the seemingly impossible mission of trying to turn my ex-girlfriend (friend zone) into attraction all over again. Weirdly enough, I've somehow established something that was extremely unexpected. Honestly, I was not gonna post about this until I had come to grips with it and actually had it all backwards engineered, but the gist of it is that it IS possible but the effort that goes into is not really worth it unless she has something you absolutely cannot miss out on (I tried this experiment just to prove to myself that the community was wrong about this topic)
Anyways, I've gotten the relationship to an ideal stage, in my opinion at least. It has been established as a "friendship" when we are with other people, BUT in private when no one else is there, it reverts to how things used to be - hard flirting and prolonged looks and all that crap. We call each other friends to each other faces, but actions speak louder than words
The best part is that it isn't actually a relationship, but more of a secret romance that has no downsides - theres no social pressure, no relationship, no worries - just pure fun and attraction oddly enough. My job now is to backwards engineer everything. For now, the prevailing theories as to why this relationship turned out the way it did, is because my target's emotional brain (the real part of the girls brain PUAs aim to tap in to) speaks louder than her rational brain (ew!) when we are together. Also, it seems to be accepted fact that girls love guilt-free, consequence-free relationships (even the ones with bf's!) as long as the PUA leads the way. I didnt realize that this was the case until 4 days ago when I sat down with some friends and discussed life.
I will try to get back to you on this one tho it will take some time.
Go for Krylon's advice for now. It's porbably the best method.