How to distinguish between good and bad tea?

What is the difference between the good tea and bad tea?
If there are no scientific instruments and approaches of identification, about the quality of tea, you can evaluate it by the color, smelling, tasting, and also the shape. Usually, we adopt look, smelling, touching, and tasting to identify.
1. Color
The different types of tea have the different color. Such as Green Tea, stir fixation should be yellow with green, baking should be dark green, steaming green should be jade green, Dragon well tea should be emerald green with slightly beige; if the color of green tea is puce and gray, the quality must be bad. Black tea should be black and smooth; the soup color is red and brilliant. Some top grade tea, about the tea soup, There is a yellow circle of tea oil around in the cup, we usually call it as the “Golden Circle”; if the tea soup with a gray and muddy color, it must be a low grade tea.
2. Smelling
A good smelling is essential to tea-leaf. Such as green tea has a sweet smelling, the green tea of top grade has orchid and chestnut smells. Black tea is fragrant, sweet smelling, and the smelling like the flowers’ flagrancy. Oolong tea has ripe peaches’ flagrancy. If the tea is not fragrant enough, generally, it should belong to the low quality tea. If the tea flagrancy got a old smelling, General it should be old tea.
3. Tasting
The tasting of tea consists of the bitter, astringent, sweet, fresh, acid and other ingredients. If the percentage of ingredients is appropriate, the taste of tea is fresh and mellow. The different types of tea, tasting is not actually same. Top grade green tea is bitter when you taste it first time, but it is a good while aftertaste. The faulty tea is insipid, even bitter. Top grade black tea gets strong taste, heavy and mellow, low-level black tea is tasteless.
4. Shape
We can differentiate the quality of tea by the shape of tea-leaf, because the quality of tea-leaf associates with its fresh leaves and the process of tea making. These can be reflected ia the shape of tea. For example, a good dragon well tea, its shape is smooth, flat and it looks like a bowl of nail. Good kungfu black tea, its clause is tight. If clause of tea is loose, loose foam particles, leaves are rough, body is light, and it could not be good tea.