Despite an occasional art/experiment page, I mostly scrap for albums, BUT being on several CTs means I have to use certain products... which in practice means I have seven year albums in various stages of completion... so when deciding on what to scrap, I try to match photos that need scrapping with kits that need to be used... sometimes if I feel a kit just doesn't fit any of my photos at all, I go with the colors and off theme.. I've been known to scrap my son's April birthday with a winter kit because I loved the blues (and ignored the snowflakes).
When it comes to actual scrapping - I usually start with the photos which then determine the general page composition (masked, framed, matted, where, how many, etc) and once I'm happy with the story flow and the journaling, I start adding elements and papers - which often come last...