I have done the project you are attempting. As it says in my bio, I started scrapbooking to use up the pictures that were displayed at my son's high school graudation party. I did an album for each of my 2 kids. The albums are similar but not identical. Each page is unique within the ablum. I started with their baby pictures from the hospital, of course I save the bracelets. Then a toddler picture and so on. Their nursery school photos and senior pictures are single photo layouts. I did a collage of the rest of the school pictures and for each sport they were involved with. For the rest I followed their activities and friends. The books begin with the newborn and end with their dorm move in.
Not a formula, but it seems you're looking for ideas and those are mine. For me it was a labor of love and really helped me put the whole empty nest thing into perspective. Good luck.