To an enviable number of CEOs and Forbes-listed elites, personal concierge Katherine Stromsland is a veritable lifesaver. From chartering Gulf Streams at any given moment to shopping for 60 relatives and friends, this svelte Nordic-Italian New Yorker makes it her mission to lighten the load of the asset-rich, time-poor.Stromsland's encyclopaedic knowledge of her hometown is no mean feat considering the city's notoriously fickle nature. So where exactly should the corporate set head? The queen of "In-the-Know" sheds light on New York's best.Hotel: Elegant or edgy?ElegantIt is hard to beat Midtown's Four Seasons for personal service and attention. Their in-house Business Centre offers round-the-clock services, including mobile phones and secretarial services. Rooms are contemporary, though the 52nd-floor Ty Warner suite has a French-Italian artisanal feel and 360-degree view of Manhattan.EdgySoho's slick-and-hip Crosby Street Hotel is popular with a younger, more eclectic advertising and media crowd. The 99-seat screening room is great for screenings, and both the slinky Crosby Bar and eclectic Drawing Room are fabulous for meeting clients over cocktails.Off the clockBook a treatment at the Four Seasons Spa, which offers a handy "Jet Lag" massage. Also in Midtown, Okeanos Club Spa offers signature Russian therapies like Platza, where you are stroked with birch branches in a traditional banya (sauna). Okeanos also offers handy express shaves, facials and back massages. On the Upper East Side, Sutton East Tennis Club is a great place to release some aggression, with eight indoor clay courts. Soho's Drive 495 offers high-tech golfing simulators of more than 40 famous golf courses.Haberdasher Lord Willy's specialises in sublime custom-made men's shirts and suits, though you will also find ready-to-wear, beautiful topcoats, ties, boxers and umbrellas. Up-and-coming Seize sur Vingt offers custom tailoring in bright colours and bold patterns for men and women, while Barker Black is the place for custom-made men's formal and semi-formal shoes that are both elegant and subversive.There is a waiting time of about four weeks, though you can opt for ready-to-wear. For must-have women's heels, try Intermix and Jeffrey. For cufflinks, The Missing Link has more than 5,000 rare and vintage offerings.Expense accountFor a power lunch, try Milanese-inspired Casa Lever. The "space age" dining room features hexagonal booths and Warhol artwork, while the private dining room holds up to 20 guests. For dinner, consider Michelin-starred Marea. Its modern Italian seafood is unforgettable, especially the sea urchin with lardo and the lobster with burrata cheese. The restaurant only books one month ahead, so be flexible with your timing for a table. Serious carnivores should make the pilgrimage to Brooklyn's Peter Luger Steakhouse.For a sublime caffeine hit, do not miss espresso bar Stumptown or the cafes inside Italian food emporium Eataly. For after-work drinks, head to Bar Basque for the impressive wine list, tapas, and outrageously crimson lounge. The Pompidou-style glass courtyard features a giant screen beaming the work of emerging artists. The older business crowd adores Bar and Books for its selection of scotch, whiskeys and cigars. Brandy Library is another must for whisky connoisseurs, while entertainment industry types gravitate to the Waverley Inn and Garden (16 Bank Street; 917-828-1154) or its offshoot, The Lion. Come here for the scene, not the food, and when booking, prepare to offer your bio. The more impressive it sounds, the better your chances.Go localA lesser-known, less crowded gem on Fifth Avenue's "Museum Mile" is the Frick Collection. Occupying a massive neo-classical mansion, this former home of tycoon and art patron Henry Clay Frick houses one of the most varied and interesting collections of European art ever amassed. Highlights include works by Cimabue, Bellini, Corot, Gainsborough and El Greco. Equally impressive is the museum's courtyard. It is a wonderful place to sit, listen to the gurgle of the water fountain and luxuriate in the Frick's peace and beauty.TransportCar services like Delroy's Limousine are often the easiest and fastest way to reach Manhattan from JFK, Newark or La Guardia airports. If the weather is bad, consider taking the New Jersey Transit train to Newark Airport or the subway to JFK. In town, taxis are usually the most convenient way to get around. If a lot of people are trying to hail a cab around you, position yourself so that you are ahead of them. Once hailed, close the door and then tell the driver your destination. Once the door is shut the driver cannot refuse the ride.Source: BBC