Pick A Theme And Repeat It
I like the idea that principles used in decorating the interior of a home can be applied to the garden as well. There are more blue & white garden art and decor ideas here too.
I realized when I visited this very large (2 acre) garden that colour was used as a theme to connect all the various garden beds and seating areas. Blue and purple flowers, blue containers, blue furnishings. It’s a common thread that draws it all together. Without this colour theme, it would not have been nearly as interesting.
This is a good idea to keep in mind if your garden is missing that something-something. Another option is to paint all the structures in the same colour (or different colours of the same value), or place a particular style of garden art or containers or flowers in clusters throughout the space—repeat something that connects it all together.
I really think the use of blue here made the garden work. See what you think: