We will draw the top view of the left wing. First draw lines for the basic skeleton of the wing. The large circle on the right is the shoulder blade, and the line on the left is the wing tip.
Draw the outline of the top of the wing just above the lines you just drew. Make sure the outline flows smoothly.
Finish the outline of the first layer of the wing. Draw the bottom part of the outline more below the guide lines.
Draw two arcs like these underneath the first wing layer.
Draw two slightly curved lines below the first arc. Draw a more circular arc below the second arc. These will be wing layer number 3.
Begin to fill in some details. Make the edge of the first wing layer more feathery, and add roundish feather outlines to the circular arcs. To the first small arc in the second layer, add slightly longer and thinner feathers that fit the arc.
Draw in the primary feathers. Note that the primaries will most likely go below the arc guide line, but that's OK! Make sure the first primary feather is slightly shorter than the rest of the primaries (i.e. fits the guide line perfectly instead of hanging like the other primaries).
Erase the guide lines and add some shading. I'm not an expert on shading, but I decided to attempt it on this wing because shading is important (unless you're drawing line art).
Congrats! You're done! :)