Sake is worth the same attention as any good wine! Testing sake is therefore in many ways similar to wine tasting. You have to look for for clarity, visuals, aroma, taste, feel and finish. gives you some tips for tasting sake:

When tasting sake you can use any sake cup, o-choko, but we recommend a "kikijogo", a small cup with white inside and two concentric blue circles in the bottom. These circles are used to check the transparency and color of sake.

The sake can be served at room temperature to chilled. The cup is poured 75% full just before tasting.

“Aozai”, a light yellow color is considered the best color of sake. If the sake is colorless most of the times it lack flavor.

Bring the "kikijogo" to the nose and swirling the sake in the cup, smell the bouquet and have a zip. Try also to smell the sake before you swirl as the difference in intensity should be significant.
Take 4-6 ml of sake in your mouth, held it for 3-5 seconds to judge its flavor. Roll it on the tongue and the aroma will fill your nose. Judge it, is it dry, sweet, thin or heavy, and then swallow it smoothly.