does your printer challenge this ultimative part?
check it out and get (almost) instant results.

these test are included in this tiny file:
size: the object is 4x50x50mm (baseplate)
hole size: 3 holes (3/4/5mm)
Nut size: M4 Nut should fit perfectly
fine details: pyramide, cone, all numbers
rounded print: wave, half sphere
minimum distance between walls: 0.1/0.2/0.3/0.4/0.5mm
overhang: 25°/30°/35°/40°/45°
bridge print: 2/3/4/5/6/7/8/9mm
surface: all the flat parts

there could be a lot of things go wrong, here the most common ones
- your printbed is not leveled (should be better than layerheigth you're printing, e.g use a Micrometre)
- your axis (Y/X/Z) clearence (with higher speed you also get problems with the moving mass)
- your slicer and configuration (every slicer handles things different and could contain bugs)
- retract settings (not correctly set you will see blobs or holes on every retract position)
- to high temperature (small details will get overheated)

Here are more infos about his part.
http://3dprint.com/48922/3d-printer-calibrating-test/