The key to this is making sure no part of clothing is just plastered to your chibi. make sure the shirt is on your chibi instead of part of your chibi. Notice the neck area how the neck is tucked into the neck of the shirt and there is an arch to show that the shirt is not part of the chibi, but on it, movable, and laying on the chibi. Make sure your sleeves and the bottom of your shirt edges are not laying on the chibi arms or torso to keep the "On your chibi" effect.