When I taste wines at home, I evaluate more than 20 different aspects of color, aroma and taste. But that's far too many considerations when sampling wines at a large tasting. Normally, these characteristics are easy to determine, but the dim lighting at most wine tastings may present a challenge. These can be more difficult to judge than color, so swirl your glass to provide more aroma. Intensity is the strength of the aromas.
Complexity refers to the variety or diversity of aromas perceived.
Body is the weight or texture of a wine in your mouth. Balance refers to your perception of the combination of sweetness and acidity in white wines, plus tannin in red wines. Length refers to how long the taste lingers in your mouth. Although I've made the case for looking at different aspects of a wine, the key to wine evaluation is how well all aspects blend. Therefore, end your short description with an overall grade for the wine.