OK, I know, not everyone wants to water color an entire background. My message here is that you don't have to create a masterpiece; you don't have to have expensive art supplies; you don't have to be an artist.
A background like this is merely an extension of the background in the photo. No details, just continue the colors and the horizon line. I probably would not have created this background at all if the photo contained that elusive kite!! Without the kite in the photo, it's kind of hard to tell what's going on other than a little boy standing in a field!! LOL But if the photo had the kite in it, then the little boy would have been really teeny in the photo.
So, starting at the beginning, I painted a pretty concoction of blues across the top of the page, let that dry. Then washed various shades of greens across the bottom and mimicked the horizon (the hill) in the photo. Let that dry. Add some deeper greens/browns in kind of a plotch method (plotch, a technical term, haha, meaning to plotch your paintbush up-down, up-down). Let that dry. I didn't want it to match exactly... just give the illusion of the photo softly continuing.
Once I was happy with the colors, popped the photo into place and added one slim strip of black and white striped paper, plus a couple of wood veneer pieces to accent.
Then at the lower edge of the photo I used a cluster of stickers and another small sliver of the black and white striped paper (cut into a banner).
This particular watercolor paper is not exactly 12x12, so I added thin pieces of the navy polka dot paper along each side. That gave a small, but defined border to the page and extended the size to 12x12.
The title came from that song in Mary Poppins in one of my favorite Thickers styles. It just feels storybook-like to me.
Anyway, it's a boy page; definitely a softer side to a boy age though! Even if you think you can't watercolor, I encourage you to give it a try. I am not a watercolorist at all. And these are cheap-o student grade watercolors.
Not "boy" tips... more like beginning watercolor tips...
Tip #1, use lots of water, adding color in layers.
Tip #2, dry between the layers of paint.
Tip #3, don't sweat putting in details.