The tasting of a wine by wine lovers, as agreeable as it may be, must comply with simple rules that we follow almost without realizing it:

Observe the wine close to light on a white background.
White wines will give many shades of colours, from transparent to pale yellow.
You must look at the colour, it must seduce you when you raise your glass: bright is indicative of a certain vivacity (especially for white wines), the clarity gives information about its health.
Do not worry if you see crystals, especially with white wines. They are crystals of tartar like you have in your pipelines or in your kettle. In this case the wine is not "modified" or "sweet": the tartar appears when the “wine gets cold”
For red wines the visual exam reveals approximate age: is it ruby, bright red or brownish, worn?
We have ten classes of smells: animal, balsamic, chemical, ethereal, spicy, empyreumatic (roasted), floral, fruity, vegetable.
You will smell the primary aromas of the wine first, without shaking the glass.
Then turn the wine in the glass, the air has its effect and secondary aromas escape.
Tertiary aromas appear about 30 minutes later.
With a little practice you will find the language of fragrance to express what you feel. Floral scents (acacia, violet), fruits (apricot, raspberry), wooden etc. …

Taste organs are located in the taste buds and on the tongue.
Sweetness:
Acidity:
Saltiness:
Bitterness:
When tasting a wine you will determine its attack, its balance, its evolution and its length.
The attack is the first sensation you feel. The balance comes from the feeling it leaves
The evolution gives the changes of the wine’s qualities during the tasting.
The length in mouth, also called aromatic persistence is the time in seconds (caudalies) during which the aroma remains in the mouth after having swallowed or spit out the wine
Beneath a certain tasting note, the wines are not retained.