Now that the transition shade is in place, apply a darker shade on the outer half of your lids. Blend it in small circles and focus on the outer corner of your crease, as well as your lash line (imagine creating a soft V-shape). To avoid getting too dark, hold your brush lightly and use gentle motions.
There is such a thing called "over-blending," which ends up muddying up your entire eyeshadow look. Avoid this by taking a moment in between blending to check how the shades are coming together. And of course, be sure to use clean brushes, since using a brush with pigment leftover will most likely not give you the color and gradient you desire. To quickly clean your brush, wipe it off on a paper towel or a cleaning sponge.
No one's perfect. You'll most likely end up having a few "oops" and "oh, no!" moments when doing your eyeshadow. To touch up any mistakes the outer corners of your eyes, you can buff them away with a damp sponge. You can also tone down your shadow by using a clean fluffy brush dipped in translucent powder on the top edge. Many people also swear on micellar water makeup wipes or a Q-tip dipped in eye makeup remover.
