About the best thing you can do to improve conversation skills is to take time each day to have a conversation. Pick topics of interest that you know your child likes- talk about a favourite movie, video game, book, family member, pet etc. Or, pick a different topic to spark their imagination:
If you could buy anything at all in the world what would it be?
If you could be any animal, what would you choose?
When you’re chatting, guide the conversation by adding comments, asking questions and guiding back to the topic, if he/she gets a bit side-tracked.