When a person wants to learn swimming he/she should get inside water. Similarly when we want to improve a language skill using the language is extremely improtant. Even small interactions with shop keepers, doctors, banks, school teachers or waiters make it a point to use English. It is easiest to speak in English with strangers.
And rehearsing before starting the dialogue is a good habit.
So the next time you get a chance try adding a new sentence with the casual "Hello. How are you!"