Liquor tasting is a little different than wine tasting. But, the purpose is the same, to find the flavor that you like the best. The best way to find the brand or flavor of a spirit that you like the most is by doing a side-by-side liquor tasting.
When doing a taste test there are three things to look for in the liquor: aroma, taste, and how it feels on the tongue.
When I do liquor tasting here is what I do:
I do a tasting of no more than three different brands of spirit at any one time. Pour about 1 oz in a snifter or red wine glass making sure to know which brand is in which glass. If possible get someone else to pour the liquor and keep track of which is which so you won't be biased by the brand name.
Next I look at the liquid in the glass to see if there is a noticeable difference in color. The color can indicate how much the spirit was aged or modified after distillation. This is not a bad thing, but just something to notice.
Then you pick up one of the glasses and examine the aroma of the spirit. Stick your nose into the glass but do not sniff from your nose. You could be overwhelmed by the smell. Instead, take a normal breath through you mouth. The aroma will enter your nose in the correct proportion.
Next, taste the liquor. Don't swallow it right away, but let it wash over your tongue to let it hit all of your taste buds.
Repeat for the remaining spirits.
Choose the liquor that you like the best don't let anyone else's opinion, price, or marketing get in the way of enjoying the brand you enjoy most.
You may also want to repeat the taste test with the liquor mixed with a mixer. For example if you are doing a taste test of Vodka, you might want to mix it with orange juice. Liquor you like neat may differ from the one you like in a mixed drink.
One last note, if you plan on doing your tasting in a bar be sure to go in when it is slow. This will give you enough time to really decide on a brand and the bartender will be able to help you.
Image courtesy of my wife...