"Parnassus suggested a massage at the Shibui Spa, in Robert De Niro's Greenwich Hotel. It's one of my favourites in New York, but hardly exclusive. Instead I requested a treatment with the facialist Georgia Louise. Emma Stone and Katy Perry fly in from Los Angeles for 90 minutes of her magical manipulation. Georgia Louise books out weeks in advance – a beauty editor I met has twice tried and failed to secure an appointment. Parnassus succeeded, with just a week's notice. My facial was bespoke, no more expensive than some at the nearby five-star Mandarin Oriental's spar and vastly superior. Of course, if you are super-organised, you can book way in advance and arrange a treatment without any concierge muscle."