Now to make it look like it's part of the image, use a fine tip black marker and draw in any lines or detail you'd like. Then I go around the edge of the whole image with a black SU marker so it looks like it was stamped.
Now in this case, since the arm is over lapping, you can cut out the arm and glue the dress to your main piece. Or what I did here, was cut off the arm just along the side of the dress and the bottom of the sleeve. Then stamp and colour another arm and slip in under the sleeve, so now the arm is on top!
For my finished piece, which you can see in this post, I added some tiny gems for buttons and voila Riley is now Sophie!
Have a Great Day!