Did you know there is an app for Copic markers? This app has some built in Combos for skin tones and hair, grass, etc and you can build your own combos too! All the current Copic marker colors are displayed with the Copic name, number and a color swatch. So next time you see a blog post or Pinterest post with a combo you want you just add it to a WANT list! You can make a list of markers you own so don't buy duplicates, called My Markers! The Combos are linked to "My Marker" list and will let you see visually through the use of a little check mark in bottom right corner of the color swatch if you have that particular color. The app also allows you to store/add your own favorite combos.
For some reason, I was unable to find the MarkerPal when I searched for it in the app store, so you can use this link to find it: http://appstore.com/markerpal I believe the app is $3.49 or $3.99. Go ahead and try this, you will love it!