By swirling a small amount of wine around in a large glass you oxygenate the wine, releasing the smells that a wine taster should be looking for. The swirl is a preparatory step for the next stage, the nose. After swirling, the taster puts the tip of his or her nose inside the glass and breathes in through the nose. It is at this stage that the wine taster should assign a smell to the wine, e.g. fruity, jammy, flowery, etc. Do not be afraid to voice your opinion of the smell if it differs from other people.
Debate makes for a good evening.
Only take a small amount of the wine in your mouth. Let it cover every part of your mouth and tongue. This is because different areas of the tongue and mouth are able to detect different types of taste. That is how to appreciate all aspects of the taste of a wine. Let the whole feeling of the wine sink in.