Usually, it's just a matter of correct ingredients. Some flaked barley, flaked wheat, carapis, etc, all can be used to aid in head retention. Caramel/crystal malts also help.
Another consideration is having bar-clean glassware. Having some soap residue, or rinse agents in the dishwasher, on the glass will kill any head on the beer.
Can you post a typical recipe, so we can see what is already in there and give some pointers on adjusting it?