Unfortunately, if you're reading this, it's already too late for you to take this step - it has to be done at birth.  The Maya would bind a newborn infant's head between two boards for several days.  This pressure was sufficient to reshape the skull on a permanent basis, leaving it elongated and backswept.  The process would have no effect on intelligence because the brain has a great deal of plasticity in infancy, and would simply accommodate itself to the new shape.
 
 

It is thought that this was done to make the head resemble an ear of corn, the Maya staple crop, and the substance, according to the Popol Vuh, from which all humankind was originally created.  The corn god himself was often depicted with this sort of elongated head, with a husk attached to it.

Of course, it was always possible, even with head shaping, that your profile wouldn't have that sleek, straight elegance the Maya so much admired.  But in such cases, there was a cosmetic creation to help you out:  the nose bridge.  What these mesoamerican equivalents of modern day glue-on fingernails were made of, I don't know.  But they served the same purpose of filling in a gap for beauty's sake.

Eye rearrangement is another thing that it's probably too late for you to manage.  The Maya found a slight degree of cross-eyedness attractive.  To achieve this they would hang a ball of resin so that it fell between their children's eyes, in the hope that this would bring about the desired effect.

But even if you can't have the proper head and eyes, you can still have your incisors inlayed with pyrite, obsidian, or jade, and your ears, nose and lips pierced to accommodate jewelry made from jade, shells, wood, etc.

And don't forget tattoos and body painting.

Headgear varied from locale to locale, but one rule always seemed to hold true: the bigger the hat, the more important the head underneath it.

If you are a woman of the aristocracy, wear the most richly-woven huipil you can find or a skirt covered with macrame-like knots and fringe.  For men, jaguar pelts from head to toe are clearly the mark of a successful Maya Ahaw.

In the Bonampak murals, you can always recognize the ruler because he's the only one wearing nifty jaguar-skin sandals.  And remember: you can never have too much jade or too many quetzal feathers in your outfit.

Some of the above may have applied only to the Maya artistocracy - throughout time and cultures, there has been a tendency for the ruling class to differentiate themselves from the common people in matters of appearance, if only because achieving the proper look required both wealth and leisure time.

Entire text copied from www.halfmoon.org/beauty.html
Drawings from the Linda Schele collection  (http://research.famsi.org/schele.html)
Photos from "Headshaping and Dental Decoration Among the Ancient Maya" by Dr. Vera Tiesler Blos.  (http://www.mesoweb.com/features/tiesler/index.html)