Hi, glad you like us. We'll gradually get there but I'll tell you a few simple Taxi phrases now since you're visiting there soon.

唔該，去+ your destination.

Please, go to _____.

m4 goi1, heoi3 _____.

呢度停，唔該。

Stop here, please.

ni1 dou6 ting4, m4 goi1.

幾錢？

How much?

gei2 qin2?

唔使找。

Keep the change.

m4 sai2 zaau2.

Hope it helps. Please let me know if you need more or if you have a sentence in mind that I didn't cover. Have fun in Hong Kong:)