Personal scrapping, I do chronological photos. So I start with all my photos of an event, like a birthday. I then see how many I have and then search the folders for things that make that event, like balloons, cake, streamers, etc. Then I find any and all photo masks that make me smile. Sometimes I will do a template if I have 4-6 photos or 30 photos. I have several templates that fit those two amounts. Then I hunt for the background papers. I tend to use 3-10 kits per personal layout. For challenges, its a different system yet not too different. I first have to hunt down the photo that fits the challenge. Then I look for the background paper and then add elements. I also try to keep challenge LO to one kit but I am not always successful.
To create an entire layout then add a photo. I wouldn't be able to do that.