The first thing you need to sharpen any pruners is a good quality metal file.  Choose one that is medium grit and that is either all one piece like mine or one that has a solid wooden handle.  Files with cheap plastic handles end up breaking and are much harder to use.

Your pruners should have a factory edge on them.  Nearly all pruners that I have seen are only sharpened on one side (as opposed to a knife where you sharpen both sides).  Be sure you figure out which side the factory edge was on and then sharpen that same side.  Sharpening with a file is done with firm strokes in one direction.  Do not rub the file back and forth on the surface you are sharpening.  This will damage the edge.  Repeated strokes with the file, down the “blade” towards the cutting edge is the correct method.

Get a nice sharp point to the edge all the way along the blade.  Try to not leave any parts of the blade duller than the other areas as that will affect your cut.

Finish your sharpening job off by applying a light coat of oil to all the moving parts to keep them rust free and moving smoothly.