Ok seems like the layout of this game is quite different than the rest of the games like Kopi Tiam, Mooncake Shop and the rest. I think because of this, players find it quite difficult to get the full 3 cherries achievement or even pass the episode!
If you are one them, not to worry here are some tips:
1) Wait for ALL customers to appear before you serve them.
2) Make all the ice cream that is requested and keep them in the cold box. Once all orders are done, serve them to the customers.
3) Certain VIP like the SingaBoy will only order a particular type of ice cream. You can prepare these ice cream and keep them in the cold box before he appears.
4) Make sure you press the "restock" as soon as possible to save time.
5) Upgrade your "restock-able" items like chocolate syrup, paper cups and ice cream flavors.
6) Save enough coins to hire "Ah-boy" to help you restock immediately without waiting.
That's just some of the tips that I can reveal for now!
Good luck and enjoy the game!