Good layout design is both dynamic and clear, creating visual points of interest that guide the reader through the content without overshadowing the message. It seems like it would be an easy thing to do, but there are few things to remember when placing photos into a layout:

Use a Dominant Photo: The dominant photos should be the best photo in a spread and be at least 2.5 times larger than the other photos.

Allow Enough Space For the Bleed: Bleed photos should extend 1 pica past the edge of the page to allow for trimming. Important content should stay 2 picas inside the edge to avoid being cut off.

Where are People Looking?: Plan your layout so that all the subjects look at the reader or across the gutter. Remember that images can be flipped but be aware of text (you don't want text to read backwards) and other sensitive objects.

Round Pegs Don't Fit in Square Holes: You don't want to force a photo into a space. Images can be resized, but their proportions have to stay the same. You should plan your layouts along with your photography but be prepared to change the layout to fit the best photos.

Variety is Important: The shape of the dominant photo should be repeated, then contrasted. Fill the remaining space with at least two photos of different sizes.

Size Matters: Resize your photos only up to 125% of their original size or images will start to deteriorate. If you can't size it large enough to fit your box, choose another image or change the layout.

Consistency Is Key: Internal margins should be the same throughout a spread or book. If you overlap images, do it the same way on all spreads.