Introduction
Like most Chinese religious traditions it is important to note the positive orientation of Daoist religious values and practices towards human life and towards this world.  The early religious ideal of Immortality (usually meant as a spiritual condition, but sometimes even in a literal sense), Longevity and their practices for obtaining them underline an almost physical dimension of the religious experience of Daoism.

Main Doctrinal tenets: Immortality and Longevity
Since the early developments of Daoism, the main religious aspiration for a Daoist has been the union with the Dao in order to maintain the balance of Yin and Yang within himself and of his spiritual (Yang-related) and vegetative (Yin-related) souls, the dispersion of which causes death. To retain and harmonize one's souls is important for physical life as well as for the unification of the whole human entity. The goal is to reach the fullest state of the Primordial Qi , which is the principle of life that in the ordinary man decays from the moment of birth on.
Because vital energy and spirituality are not clearly distinguished, old age in itself becomes a proof of sainthood. The aged Daoist sage became a saint because he had been able to cultivate himself throughout a long existence; his longevity in itself was the proof of his saintliness and union with the Dao.
The long and complex Daoist traditions developed various kind of practices for obtaining this kind of Immortality or Longevity: Some followed a regimen of gymnastics and observed a form of macrobiotic diet. Others practiced quietistic meditation. Others practiced the art of alchemy, assembling secret ingredients and using laboratory techniques to roll back time. Sometimes this refining process was carried out by imagining the interior of the body to function like the test tubes and burners of the lab. Personalized rites of curing and communal feasts alike can be seen as small steps toward recovering the state of health and wholeness of Primordial Qi.

Main rites and practices: Quietistic meditation
In quietistic meditation, sometimes described as "sitting in oblivion", the adept endeavors to return to his or her original nature, which is a manifestation of the Dao in its undifferentiate, chaotic form. Emphasis is placed on “inaction”  Wu Wei (see p. 3) simplicity and spontaneity in order to to deliberately cut off sense perception, to lose bodily awareness and remove all thoughts from consciousness. See Source 1 chap. 11.

Main rites and practices: Daoyin gymnastics
Daoyin literally means “guiding and stretching,” and is a traditional Chinese form of  “gymnastics”. Traditionally and historically speaking, Daoyin practices are stretching exercises, usually combined with specific breathing patterns. The earliest forms of Daoyin were developed during the 206 BCE-8 CE in the context of health and longevity as well as therapeutic movements. In contemporary Daoism, this gymnastic in the form of stretching routines aimed at health and longevity, has been eventually incorporated into larger Daoist training regimens. The earliest Daoist reference to Daoyin practice appears in chapter fifteen of the Zhuangzi in relationship to the quest for Longevity. See Source 1 chap 15.

Main rites and practices: Alchemy
Daoist alchemy has a history of more than two thousand years, recorded from the 2nd century BCE to the present day. It is characterized by a foundation in doctrinal principles first set out in the foundational texts of Daoism — especially the Daode jing (see p.3) — concerning the relation between the Dao and the world. The cosmos is conceived of as the last stage in a series of transformations that cause a sequence of shifts from the undifferentiated Dao to unity, then to duality (Yin and Yang), and finally to multiplicity. The alchemist's task is to retrace this process backwards in order to reveal the purest presence of the Dao in the materials they experiment with. Alchemy is variously said to grant transcendence (a state described as "joining with the Dao"), Immortality , Longevity, healing protection from spirits and demons.  Another branch of Alchemy, called Internal Alchemy, developed from the 8th century CE. It borrows a significant part of its vocabulary and imagery from its antecedent (see more on p. 8).

Deities and other holy beings: Immortals
The religious ideal of Immortality gave birth also to the fantastic imagery of Immortals, who began as human practitioners of Daoist immortality techniques but finally conquered death through achieving the unity with the Dao. Some of them, called  The Eight Immortals came to be worshiped and considered to be signs of prosperity and longevity.

Source analysis and comment
Source n° 1
Glossary:
Peng Zu (Ancestor Peng) is a legendary long-lived figure in China. He supposedly lived over 800 years
Excerpts from the Zhuangzi
Ch. 11
See above: Main rites and practices: quietistic meditation.
Ch 12
See above: Main rites and practices: Daoyin gymnastics.

Source n° 2
Excerpts from the Jiudan jing
Glossary:
Divine Elixirs; Elixirs of the Nine Radiances : names of the various of elixirs which grant various benefits.
Chamber of the Great Medicines: name for the alchemical laboratory.
Often in Daoist Alchemy compounding an elixir is part of a larger process that consists of several stages, each of which is marked by the performance of rites and ceremonies. It is this process, and not merely heating the ingredients in the crucible, that constitutes the alchemical practice. Building the laboratory, kindling the fire, and ingesting the elixirs all require offering pledges to one's master and to the gods, observing rules on seclusion and purification and performing ceremonies. Instead of being seen as mere appendages, these ritual acts are deemed to be as essential to achieving an elixir as are the ingredients. It is not the case of this text, but later alchemical texts will make great use of the correlative theory of the Five Agents (see p. 2).

Source n° 3
Daoist Immortal Lu Dongbin
The Daoist Immortal Lu Dongbin is the chief of the Eight Immortals (see above). He travels through the clouds riding on a dragon (representing the Dao). In his left hand he holds a bottle of the elixir of Immortality, which he has uncorked. The elixir fragrance has wafted upward and has become another, smaller dragon (upper right). His supernatural powers are in fact quite natural because he is in perfect harmony with the Dao.  The fact that this is a Japanese painting suggests the spreading of Chinese and Daoist Culture outside the boundaries of China.

Intercultural and interdisciplinary information
The Daoist correlative approach in Alchemy presents similarities  with the western Hermetic tradition rooted in a similar correlative cosmology, whose base were laid in early Greco-Roman alchemy, based on five elements (earth, water, air, fire and aether), and transmitted through Islamic alchemical traditions in the form of alchemical and Hermetic cosmological texts which were translated into European languages during the Italian Renaissance.
For more info see:
http://www.esoteric.msu.edu/VolumeVI/Dao.htm par. 34
Various types of alchemical traditions around the world:
http://www.britannica.com/EBchecked/topic/13282/alchemy