How do you properly taste a beer? If I want to fully appreciate what a beer is offering, how do I properly taste the beer to reveal all the nuances in the aroma, flavor and aftertaste?
Beer Advocate's Guide is a decent one.  The abridged version is:


Look at the beer.  How's the color and head?
Swirl it a little bit to pull out the aroma
Smell it.  Swirl again if need be.  I recommend taking a 20 second break after smelling, then smelling again, since if you smell too long, your nose gets used to it and it becomes harder to pick up the notes.
Sip it.  Don't swallow immediately, but keep it on your tongue for a moment.  Breath out with it still in your mouth and pay attention to the resulting smell (unless you just ate a bunch of garlic before the beer).
Taste again as the beer warms up a bit.