How can I distinguish a sipping tequila? What are the characteristics of a sipping tequila? What should I look for except Best Sipping Tequilas of 2021 list on the Internet? Is it a special ingredient or some inscription such as reposado?
The truth is that Tequila is a sipping alcohol, on the whole.

“In Mexico, tequila is kept in the fridge so it’s perfectly chilled
when served and almost always enjoyed neat,”

according to Angel Bolivar, the head bartender at Casa Neta in New York City.
Of course, as with any alcohol, throwing as much money at it as possible will generally get a person something that comes from the higher shelves and is 'better' and more delicious than some of its competitors. However, you never need to break the bank in order to partake in a fancy and delicious beverage.
Knowing the different types of Tequila is the best way to begin one's search... At the most basic level, there are essentially 2 types of tequila:
1.) &quot;Mixto&quot; or mixed - anything can be labeled as Tequila as long as 51% of the fermented sugars come from the Blue Agave plant. Therefore other sugars and additives, like cane sugar, caramel color, oak and other flavorings, glycerin, and sugar-based syrups, can make up the other 49%... generally any tequila labeled &quot;gold (oro)&quot; and &quot;joven (young)&quot; is going to be a mixto.
2.) 100% agave tequila - this is the stuff that you will want to sip. Leave the cocktails to the mixtos.
From there, the tequilas can be broken up into the way that they are aged. There are essentially 4 classifications of aged tequila  that is made from 100% blue agave:
1.) Blanco (white) or Silver - this would be the youngest type of tequila. The liquid is clear because it never sees the inside of a wooden cask.
2.) Reposado - means &quot;rested&quot; and is usually aged for more than a couple months and up to a year.
3.) Añejo - means &quot;vintage&quot; and is aged from one to three years.
4.) Extra Añejo - also &quot;ultra añejo,&quot; is going to be tequila aged for more than 3 years time.
I have heard recommendations that beginners should start with sipping white tequilas but, I would vehemently disagree... in my experience, the whites are more &quot;harsh&quot; and fiery. They do not have as many subtle notes or nuanced flavors before and after being in the palate. Morgan Hurley, marketing and beverage director of Mex 1 Coastal Cantina in Charleston, S.C. states;

“Blancos showcase the terroir and the agave, but they also show any
imperfections.”

TLDR: Any 100% agave tequila labeled &quot;reposado&quot; or &quot;añejo&quot; is going to be your best choice for sipping - though not mandatory, set your budget for around $30 and up for the best experience.