When contouring your face, you'll need an angled blush or sculpting brush such as Make Up For Ever’s Double-Ended version, $39. You want it to be dense but still fluffy for the most natural look. Pick up some product on your brush and remove some of it onto your hand, this way you still have pigment on the brush but it is evenly distributed and you won't get any streaks. Apply the bronzer under your cheekbone stopping about half way in a small circular buffing motion. Back and forth swipes will result in a harsh line that you'll need to fix. If your face is very wide, extend the contour up your hairline onto your temple, this will create a shadow that visibly slims the face. If you have a very high forehead, you can apply some to the top of your hairline to add dimension to the top of your face. Always apply blusher after you contour as you'll need to apply with discretion to avoid looking like you have too much makeup on.
If you have very puffy or flat eyes, use a crease brush and apply some of your bronzer into the socket line. Extending the stroke into the inner corner of the eye can also create depth.
If you have a wide or crooked nose, applying a small amount of product to the outside of your nose, following down from the inner crease of your eye can make your nose appear straight and defined.
Another very popular place to contour is under the chin. This will hide any sagging skin or puffiness around the neck. Using the same brush as you used on your cheeks, apply product under your chin and along your jaw line sweeping it up towards under your ear.
Using the same techniques from your face, you can help define some of your other assets with contouring too. Apply bronzer under your collarbones to draw attention to your decolletage or in between your breasts to give the impression of more cleavage. Be careful about attempting to contour areas such as your abs or arms as, if not completely blended, it will be very obvious that it's makeup.
After you use the bronzer and feel confident that it is well blended and natural looking, apply a highlighter on your cheek bones, if applying it to the face, or brow bone, if you're contouring your eyes, to get the most definition.