There is a newer "advanced" guide: http://www.sirc.org/publik/advanced_flirting.shtml
Note that the "advanced" guide almost doesn't have any of the HOWTO advice from the OP link, however I've read and would recommend to read both: the "advanced" guide helps put things in perspective.
Also, I think the following quote from the "advanced" version is brilliant:
The human species is addicted to rule-making. Every human
activity, without exception, including natural biological
functions such as eating and sex, is hedged about with
complex sets of rules and regulations, dictating where, when, with whom and what manner the activity may be performed. Animals just do these things; humans make an almighty song and dance about it: this is known as 'culture' or 'civilization'.