There are lots of cheap and nasty tequilas out there, one of the most important factors when choosing a tequila it that it's made from 100% blue agave plant. This gives the tequila the true taste of the agave plant but doesn't always necessarily mean a high quality product, but it's a good start. It should state "100% Agave" on the bottle.
Good tequilas should be compared to a good malt whiskey. Despite its reputation as a drink to slam, many tequilas deserve to be sipped and savoured.
Choose a tequila which suits your drinking method, don't buy a £300 bottle of Añejo to drink slammers all night and you probably wouldn't want to sip a £10 bottle of mixto from the supermarket.
Choose a blend:
The blends show the quality and age of the tequila. Each blend has a different taste so it's worth finding the one you prefer.
It's helpful to read the label before choosing your tequila and understand just want your getting for your money.
If possible try tasting a few different types of tequila and you'll probably find your preferred brand and blend. It's handy to have a range tequilas for different purposes, a tequila gold or Reposado is nice with a squirt of bitter lemon or a good quality Añejo makes a nice sipping tequila.
Carrying on reading for more tips on reading the label.
Lots of people make the mistake of thinking tequila bottles should contain a worm but this is completely untrue!
If you're drinking from a bottle with a worm in the bottom then you're not drinking tequila. It will be a spirit known as Mezcal or Mescal which is made from the agave plant (not the blue agave as tequila is made from). It has a much more smokey flavour and is usually drank straight. Not all bottles of mezcal contain a worm or more accurately a larva of a weevil which is actually a pest to the agave plant.