A couple other things that can help:
1. Only wash your glasses with hot water, no soap and definitely no dishwasher with jet-dri.
2. What do you use as a fermenter? The reason that I ask is, the foam positive malt protiens that are largely responsible for head retention are also picked up in krausen formation. If you use an undersized fermenter and a blowoff tube, AND ROUTINELY HAVE SINIFICANT BLOWOFF, you are permanently removing those protiens and that can affect head retention. The effect may not be pronounced with all styles as hop compounds also contribute to head formation and retention, so highly hopped beers have a secondary source, but lightly hopped (especially lower gravity) beers this can be a major problem.