A long time ago, someone showed me this page wherein a d20 gamer explains his tabletop miniature painting technique of scribbling on them with markers. No, I am not kidding. He shrinks down the photos he takes to demonstrate that they look just fine from a distance. Sir, I strongly encourage you to steer clear of CoolMiniOrNot if you have a fragile ego.

Here is his functional finished work:
Rar. I represent a role-playing encounter.
But I found myself thinking back to that technique and wondering, "Could it work?" He clearly did the opposite of highlighting/shading by over-marking the skeleton with black, but could I add one more step familiar to all mini painters and make it work? Perhaps....

So on a lark I bought a pack of cheap colored markers (Sharpie equivalent but not official Sharpies) at the dollar store, which then sat ignored for a couple years. All those skeletons that came in my Reaper Bones kickstart reminded me that I had wanted to try this, and now I have lots of cheap fodder.
The Skeleton and the Markers. On sale in paperback this week.
 The brown marker had dried up completely, even in the unopened package, so I had to use yellow for the spear shaft. The shield got orange (the closest thing to red I had) and yellow edges/center. The spear tip was colored with a silver metallic Sharpie I found (not a paint marker, just a regular old Sharpie.) So at this point pretty sad looking and yet still better than the "highlighted black" example.
What I lack in contrast I make up for in affordability.
I then did what gamers have done since the dawn of time.... I gave him a liberal washing of brown, in this case Citadel Agrax Earthshade. I mean very liberal. It took a while to dry. When done, it was remarkably passable.
I've certainly seen worse on the table.
So have I revolutionized the miniature painting technique pool by using markers and dip? Not quite. Does it make a passable skeleton? Possibly. Does it look good compared to the "only marker" attempt? Oh yes.