New Age spirituality is a blanket term covering several different belief systems. There are a few general beliefs that are commonly shared among these systems, but there isn't really a single thread of New Age belief. Many people who identify with the New Age movement also identify themselves as practitioners of other religions, like Hinduism or Christianity. Sometimes the New Age movement is associated with certain self-help programs, while in other situations, it may be associated with psychic abilities or reincarnation.
There is no particular holy text associated with the New Age spirituality. Many people who fall into the New Age category do believe in a god, but don't have a specific faith they ascribe to. Some New Age believers are also disaffected people from other faiths who have turned away from their former beliefs for a variety of reasons. Overall, the New Age movement is generally growing in popularity despite suffering some fierce criticism during the early stages of its development.
The sources for New Age spirituality are often rooted in very old religious practices, but the actual movement became popular in the 1970s. It was generally seen as a reaction against the dominant religions of the day, and most New Age believers are opposed to the singular exclusive natures of many religions, because they believe that these kinds of beliefs can be divisive and hurtful. Most New Age belief systems allow their users to incorporate religious ideas from many different sources, and they generally don't believe in exclusionary practices.
Some of the common beliefs in New Age spirituality include reincarnation, spiritual evolution, karma, and pantheism, which is the belief that all things in the universe are aspects of god. Many New Age practitioners also believe in things like aura's and channeling. Crystals are sometimes considered as sacred items, and some kinds of New Age spirituality hold a belief in astrology.
New Age belief systems often have close associations with unconventional healing methods, like homeopathy and acupuncture. It is also fairly common to see a mix of spiritual beliefs with psychology as a way to heal the mind along with the soul. In fact, the mix of science with spirituality is a common theme in the New Age movement. For example, many New Age practitioners have very strong spiritual beliefs associated with the natural world, and they are often very heavily involved in the fight against global warming.