When analyzing a beer, you can't just swill it down, burp and say "it's great" or "it's crap." Even though tasting is an individual art, there are a few steps, which if followed, will take your beer tasting to a blissful level.
Take pause and marvel at its greatness before you partake of it. Raise the beer in front of you, but don't hold your beer to direct light as this will dilute its true color. Describe its color, its head and its consistency.
Swirl your beer gently in the glass. This will pull out aromas, slight nuances, loosen & stimulate carbonation and test head retention.
Breathe through your nose with your mouth open, then breathe only through your mouth (nose and mouth are connected in the experience). Let olfaction guide you. Agitate again if need be, and ensure that you are in an area that has no overpowering aromas. Enjoy its bouquet.
Now sip the beer. Resist swallowing immediately. Let it wander and explore your entire palate. Let your taste buds speak. Note the mouthfeel, the consistency of the liquid's body, and breathe out during the process of tasting. This process of exhaling is called "retro-olfaction" and will release retained stimulations at the mucus and mouthfeel level, but at a higher temperature. At times this will be the same as the olfactory process if not different and complimentary. Try to detect any sweetness, salty flavors, acids and general bitterness. Explain what they are, or what they are similar to.
Try tasting the beer after it warms a bit (just a bit mind you). Really cold beer tends to mask some of the flavors. As a beer warms, its true flavors will pull through, become more pronounced.