Read previous sensory evaluation articles - The Basics, The Language of Wine, Wine & Bullfighting.
'Proper' sensory evaluation of wine actually involves a surprising amount of knowledge. Indeed, there are entire courses dedicated solely to this discipline. Starting off with the basic knowledge is necessary, then it becomes a 'practice makes perfect' scenario.
The basic technique for sensory evaluation goes as follows: pour wine, look, sniff, drink. Let's look at the three senses we use for sensory evaluation: