The power of the vignette... 5 min sketch

I was sketching on a project today and I was running out of time... I decided to try out an old trick to pull it together, the vignette.
I drew these shoes very quickly and without much detail to illustrate what a difference the addition a simple vignette can make. 
As you can see above, the vignette helps the composition of the page.  It's brings the two competing sketches together and creates a nice harmony.  The vignette also add a sense of depth and horizon line so now the object aren't floating around.  Personally, I think a vignette works best as simple lines and not big blocks of color but sometimes that works too.