For all RMD users that own a mouse , some techniques that may help you on the quest of drawing eyes ^^ (how to use all drawing tools and half from the ink on it)
First choose the canvas color (here -> grey canvas color , R:179 , G:179 , B:179 ; then choose white with transparency(30 in this case) and use the fill tool to draw the eye ball. with a bit of grey shade the right part of the eye ball . then choose the color for your iris (in this case , blue) and draw it using the pencil (with transparency in this case).
Now , shade with black using transparency (one or more layers , depends on the type of black you get using transparency).
Then use darker grey and black to shade the superior and inferior eyelids. You can use the fill tool to draw textures (like I did here) and the airbrush on dark black for the superior eyelid.
Notice how the superior lid is darker than the infirior lid...
Now , shade smoothly the face (the skin) with black , white and grey tones of color , using the airbrush.
Then, draw the eyelashes using fill tool with transparency , the pencil on its first size with very litle transparency (like 80 % , or 90%). Notice how the eyelashes aren't equal , or placed at equal distances. Thats a first factor that makes the eyelashes look natural.
Then add color to the iris( with pencil or fill tool , using transparency . you can make straight lines or curves.) and reflection .
Finnaly , nail the drawing adding some few details.
Hope i could help you by submiting this tutorial.
Have fun drawing!