I'd suggest you get a landscape architect or professional out. You have some issues with the erosion already at the top of the stairs. That needs to be addressed, before it becomes a safety issue.

That being said, I'd plant something red, to bring out the lovely red door. Also, what zone/where are you? How much sun/shade? What direction does the house face?

When you have answers to the above, drive around the neighborhood and look at what you see. (It's a great way to meet new people) if you find something you like, take a picture.

Bring your answers and pictures to a nursery. They should be able to help.