Design what you want to build.
Credit: Cubify

In order to print something on a 3D printer, you have to have a 3D model that's in a file format your printer understands. At the high level, where you start from scratch and build something from nothing, you'll certainly need to have some technical skill, but you can easily design basic objects quickly by using one of the several free or low-cost software applications available. "When we started, there wasn't much that was available that people could use to get into it," Pettis says. "Now there's plenty of stuff you can experiment with and get into – for free!" He recommends starting with Autodesk's free 123D, or the current version of SketchUp (it used to be Google software), which is simple enough to figure out in a few hours.