How do you tip in Hong Kong?

So, let me ask you this - how exactly does one go about tipping in Hong Kong? I've heard it's a bit of a different culture when it comes to leaving some extra cash for good service. Is it customary to tip in restaurants, cafes, or even taxis? And if so, what's the general amount or percentage that's expected? Do service staff appreciate it, or is it seen as unnecessary? I'd love to know the ins and outs of tipping etiquette in Hong Kong to make sure I'm respecting the local customs.