YOUR BEST MATE'S SISTER

Why you shouldn't "Blood is thicker than water," says Siski Green, author of How to Blow Her Mind in Bed. "You're risking a relationship that has been built up over years for one that might not last."

Why you should "You have a lot in common, which is a strong basis for a relationship," says Dr Pam Spurr, author of Fabulous Foreplay. "If she's younger, she has quite possibly had a crush on you, too." That's what's known in the trade as an "in".

The next move "Prep your friend by mentioning a recent pay rise," says Green. "Indiana State University research found family members have a massive influence on women's choices and male family members want her to date a good provider. He'd rather she didn't date anyone, but you can become his next-best option. And calm his over-protective instincts by not being too touchy-feely when he's around."

YOUR CHILD'S TEACHER

Why you shouldn't "Parents' evenings are awkward enough without come-to-bed eyes across the table," says Kate Taylor, author of Not Tonight, Mr Right. "She's a big influence in your child's life. If you screw up, will junior suffer?"

Why you should "If you're a single parent, new people are hard to meet and you already have common ground," says Spurr. "Plus she likes children." Well, you'd hope so anyway.

The next move "You probably have a three-minute slot to make an impression, so apply speed-dating tactics," says Green.

"Make eye contact, mention you're taking your child for pizza and ask what her favourite topping is. This open-ended question will draw her into conversation and she'll feel she has disclosed private information to you. Harvard psychologist Dr Zick Rubin found eye contact and disclosing personal info are the keys to making someone fall for you."

THE WORK-EXPERIENCE GIRL

Why you shouldn't Think Monica Lewinsky. Dribbling over 22-year-olds marks you as the office letch; you'll lose colleagues' respect and blow your chances with any other women.

Why you should "You're pursuing the same career so have plenty in common," says Taylor. "As soon as she's packed up her desk, you've got the green light." As long as she's not heading off to finish year 12.

The next move "Asking her out should be the easy bit - women are wired to be attracted to high earners, and if she's prepared to work for free, she's probably ambitious," says Green. "Ask her out for a drink on the pretext of giving her some career pointers."

If things progress, dodge the cradler-snatcher jibes by getting it out in the open. "A study in the Duke Journal of Gender Law & Policy showed men who enter workplace relationships because they have authentic romantic rather than lustful feelings generate positive office gossip," says Green. "Tell the office hyenas you have a 'genuine connection'."

THE GIRL YOUR MATE IS AFTER

Why you shouldn't "There's no bigger blow to a man's ego than to be rejected in favour of his friends," warns Taylor.

Why you should "You've got the same taste in music, films and friends as your mate, and this will inevitably extend to women to a certain degree," says Green.

The next move "Don't make it into a competition," warns Green. "Instead, set him up with someone else. His attraction for the other girl will decrease as his oxytocin levels start to rise in reaction to the new girl."

YOUR BOSS'S DAUGHTER

Why you shouldn't He holds your financial testicles in his hands. Averted eyes over the breakfast table may not up your chances of promotion.

Why you should She's out of bounds, so while most people will look, very few will touch. "She is very powerful by association, and power is a mighty aphrodisiac," says Green. "This means most men will be too scared to approach her, so the field is clear and she may be grateful for your advances."

The next move "Two of the main traits women find attractive are power and self-confidence," says Spurr. "A man who takes a risk exudes power and you can score big just by making a mature, confident approach. Don't go to great lengths to impress her - if you'd take a first date to a burger bar then take her there. The key is not to be in awe of her status, which will allow her to relax and enjoy herself." Good luck with her dad!