The theme should be on top 1200 x560 , should contain photo, time/title/venue.
match the panel color, pattern , buttons, photo panel etc accordingly
Don't make too glossy. Matte finish preferred.
Keep US customers in mind before picking color palette.
the top panel should contain the theme /card and bottom can be some pattern/color. The attached file shows the illustrations in the bottom panel in one of the design. WE DON'T want that. I have attached other which shows illustrations on top but it's too narrow.
This is just one theme. We will need 100s of them, so make a good effort so that we can assign you the bulk.
I have attached couple files to show how you can do the theme. Note that there are lots of content (as shown) in all the inytes.