Begin with one complete order
The catalog includes an iced milk tea order beginning with 唔該. That polite opening is a useful choice in a service exchange. A hot coffee example follows the same idea with a different drink.
Listen for the entire rhythm, then swap only the part you know. Replacing English words one by one will not necessarily produce a natural Cantonese order.
Make a small change to the drink
少甜 asks for less sweetness; 走冰 asks for no ice. Both are short, useful additions when they fit the drink you are ordering. Practise the complete order before adding a customisation, so you can still communicate when the exchange moves quickly.
A staff member may ask whether you are eating here or taking the food away. That line is useful to recognise even when it is not something you would say yourself.
Finish the exchange
唔該埋單 is a compact way to request the bill. If you are offered something else, 唔使喇，唔該 gives you a polite “No, thanks.” These closing lines make a restaurant visit feel like a conversation rather than a single memorised order.
For practice, play the order, a likely staff question, and your closing line in sequence. This prepares you to listen as well as speak.
More phrases for food and drinks
The guide above is a starting exchange. These other recorded phrases help when the conversation takes a different turn.