There are many techniques to be more effective. The first is to use WhatsApp from your computer, using WhatsApp Web or via the Callbell platform.
This will allow you to manage a greater number of chats in a more organized and structured way.
Another method is to use Quick response templates that allow you to save and reuse the messages you send most frequently to quickly answer the most common questions.
One last piece of advice: set up a welcome message that will be sent every time you receive the first message from a customer and a message for when, on the contrary, you will be absent and that will be sent outside the established business hours.