In Singapore as in Hong Kong, don't ever toss your business card nonchalently to your would-be client/customer/acquaintance. Hand over business cards with both hands, as though you are handing over your inheritance. Bear in mind that your card should have its typeface facing the recipient. Likewise, receive cards with both hands. Never, never, scribble on them or worse, fold it in half like a calzone ( italian pizza puff ).
When someone hands you his/her business card, they will do so with both hands and you have to recieve it in both hands, look at it, acknowledge it and then put it into your pocket. Otherwise, it is considered quite rude. Whatever you do, DON'T write on a business card infront of the person that gave it to you!
Should you have the need to hand out business cards in Hong Kong, it is local practice to do so with both hands. Make sure you bring plenty. Handshaking is the most common form of greeting in China. The Chinese also give a slight nod or bow when shaking hands.
The Chinese are fairly conservative in dress, should you decide to wear anything of the revealing nature, be prepared for stares.
This is the "how to" for receiving and giving a business card.
When a person faces you and holds their business card with one, or more commonly two hands, be sure you face them, take their card with both hands, read the card for 2-3 seconds (or pretend to read it if you have to pretend), and then look back into the giver's eyes and thank them (ie. say "xie xie" (pronounced "sheh she") or thank you).
When you go to give your card to someone, hold it with both hands so they can reach out, take it and read it as it is positioned in their fingers, without them having to turn it right-side up or flip it over.
Pay attention to others when they get or give cards. It's definitely an edicate thing.