Here's another sketch that I did that I modified in Photoshop. I drew the image on watercolor paper using Intense pencils and blended the colors with water. Then I scanned the image into my computer and altered the background.
The first one was just a texture and mud toned page. Because of the pale, almost drab colors, the vibrancy of the sketch shows through.
In the second piece, I added a gradient background and some more texture. The colors are pulled from the sketch, so they all come together.
In the third piece, I went for a different look, adding a patterned background (postal marks) and shadowed the edges. This works because of the muted color and the black images.
The final piece is just a fun piece of a bright color along with a pattern. I chose the orange/yellow background because it complements the blue of the jar.