I stumbled upon color palette generator recently. It creates a color palette base on a photo you selected. This is a useful tool because you can simply upload the photo and it shows you all the major colors that are present in your photo. Below is an example of a photo I tried with this tool and a layout I created using this palette:
A big majority of my palette were muted grays and blues so it's my primary shade on this page. I used dark browns as my accent color and everything came together easily.