I managed to do this today and it took me a long time to figure it out.
The first thing you do is scroll to the bottom of the "My Day" screen. There, you will find "Edit My Day". Select that and you can select the "Cards" you want and the order you want them to appear. This didn't fix my problem since, apparently, I only deleted the card for today. My problem was solved by touching the "Restore today's dismissed cards" button.
This is all fairly obvious unless you never scroll to the bottom of the "My Day" screen.
