Things You'll Need
Very fine round paintbrush
Dark brown or black paint
Eyes are one of the most difficult features of the human face to capture in paint. You must pay particular attention to detail -- if you want to give your work a life-like spark -- and eyelashes are a pivotal component of this. As with all painting, you will need to observe your subject carefully, noticing how human eyelashes tend to curve slightly down on the bottom, slightly up on the top, and slightly towards the outer edge of the eye. You will also need a very fine paintbrush.
Paint the base of the eye first, including the whites, the iris, the lid, and the under-eye.
Take a long, careful look at the eyelashes of your subject. Notice if they clump or stand out in single strands, and observe how long or short they are.
Make a couple of small, fine strokes on the top lid -- curving slightly up, and slightly towards the edge of the eye -- with a very fine, round paintbrush.
Make one or two similar, but smaller strokes on the bottom lid. Use decisive but delicate movements. Children and men usually only need the very slightest hint of eyelashes, so only add one or two small lines at first. Do not make the lashes too long, or they will look cartoonish.
Keep the lashes a little scraggly, rather than all the same length, and taper them off at the ends. Paint them in slightly different directions to give them an organic feel.
Step back and observe your work. Add another stroke or two, if you feel the eye needs a little more. Women generally have thicker, longer lashes, so they will probably need more definition.
If you are using airbrushes or Photoshop, the same principles apply.