Money is as shy and elusive as the “old time” maiden. It must be wooed and won by methods not unlike those used by a determined lover, in pursuit of the girl of his choice. And, coincidental as it is, the POWER used in the “wooing” of money is not greatly different from that used in wooing a maiden. That power, when successfully used in the pursuit of money must be mixed with FAITH. It must be mixed with DESIRE. It must be mixed with PERSISTENCE. It must be applied through a plan, and that plan must be set into ACTION. -Napoleon Hill #TGR

There are authors like Mark Manson who went from pick up artists to self-help gurus but this connection is kind of faint. Maybe it's the fact that pick-up artists tend to be non-spiritual (perhaps because they subconsciously view spiritualism as feminine), but the root of self-help thinking such as the "law of attraction" is always spiritual.

Sure you can explain away the law of attraction's spiritual roots by claiming that it only works because desiring something induces you to change your behaviour. However to me that feel like a crude post-hoc rationalisation.