Prepare, prepare, prepare ...
You may think all radio hosts are witty and improvise during their shows, but the truth is, a lot of planning goes on behind the scenes to ensure shows sound seamless.
"To make sure the programme is fluid, we do a lot of preparation," Hau says.
The Teen Time host gets ready by going through the top 10 singles chart in Britain every Monday and the top 10 US Billboard chart every Friday.
Hau makes sure that all of her CDs are in good condition for broadcasting, but also selects backup tracks in case something goes wrong.
One of her jobs is to prepare catchy "idents", which are short messages or jingles that help make her show more memorable to listeners.
Hau also does a lot of editing to shorten songs to play during her show; she says this can make new tunes more listener-friendly.
The six beeps
If you listen to the radio often, you will have noticed the six "beeps" before each hourly news segment on RTHK. Radio hosts are given instructions not to talk over them.
These six beeps represent the last six seconds of an hour. The last beep is timed to go off exactly when the minute hand on a clock strikes 12.
Let's get equipped
Imagine speaking to 600,000 listeners every morning. That means nearly one in every 10 people in Hong Kong is listening to your voice coming through the airwaves.
The variety of equipment in the studio is very impressive. Little did we know that choosing a proper pair of headphones is a science.
Hau dons a pair of Technics, but she says some of her colleagues prefer Pioneer. There is a difference: Technics give her the tempo and bass she needs as a music-show host, and Pioneers cater to talk-show hosts who need to monitor their own voice.
One interesting fact is that the RTHK Radio 3 studio is still using close-to-extinction MiniDisc (MD) systems to play some of their music. Hau says this is because MDs have the best sound.
The 'dump' button
The spontaneity of radio is both its beauty and its vice. It comes in the form of audience interaction, through phone calls and text messages. Hau even gets song requests on Facebook.
However, sometimes mistakes happen, and the host gets very little time to respond.
What if someone swears while a show is airing live? It is easy to edit out mistakes on a pre-recorded programme, but what happens on a live one? Meet the "dump" button.
During a live broadcast session, there are always a few seconds of delay between what happens in the studio and what you can hear on the radio.
When the "dump" button is punched, it allows an unwanted part of the conversation to be removed. At RTHK, the delay is only three seconds - most radio stations have a seven-second delay.
It is, therefore, a real challenge for radio hosts to stay on their toes and be ready to hit the "dump" button.