Though there are no formal or definitive boundaries for membership, those who are likely to sample many diverse teachings and practices (from both 'mainstream' and 'fringe' traditions) and to formulate their own beliefs and practices based on their experiences can be considered as New Age. Rather than following the lead of an organised religion, "New Agers" typically construct their own spiritual journey based on material taken as needed from the mystical traditions of the worlds religions, also including shamanism, neopaganism and occultism.
New Age practices and beliefs may be characterized as a form of alternative spirituality or alternative religion.
In that regard, I'm like a Vulcan. I believe only in what you can prove with facts and evidence and logic. If there's no reason to believe in something, then I don't believe in it.
In contrast, both the religionist and atheist are sure of their beliefs, even though neither one has proof. They have faith that their position is the right one. Agnostics aren't like either type of believer because they have no definite beliefs.
New Agers have all sorts of religious and spiritual beliefs. But atheists, who are certain God doesn't exist, may have some beliefs aligned with New Ageism. For instance, they may believe the universe is filled with a "force" that isn't God but is supernatural. Or they may believe in the healing power of yoga or meditation or aromatherapy.
As an agnostic, I have no spiritual beliefs whatsoever. I'm the opposite of a New Ager, who tends to believe in anything and everything spiritual. No one in existence is less of a New Ager than I am.