The smart way to deal with unresponsive clients

How do you encourage a client to really open up?
Every financial adviser experiences a client or potential client not responding to them.
A typical scenario is that you have had a conversation(s), and the ball is now in the client’s court, but you hear nothing as time ticks by.
It might be a proposal, an application, or some task a client needs to deal with before you can move on.
What do you do in these situations?
Do you wait? Do you keep chasing? Is there a better approach?