3D-Drucker/Blender

How to Create a 3D Printable Blender Model

Using Blender to create 3D printable models is easy, if you remember some stuff:

Make sure you do not have duplicate vertices: [editmode] W -> Delete Doubles
Always make sure, your objects are manifold: [editmode] [deselect all] Ctrl + Alt + Shift + W
Make sure all normals of your faces are pointing outwards: [editmode] [select all] Ctrl + N
Slic3r seems to have problems with coordinates below z-zero from time to time, move your object accordingly.
Select the objects you want to export, export to STL and have fun!