Zoroastrians believe the world is a battlefield between good and bad. It is everyone's duty to fight evil, on both a physical and spiritual level. Zoroastrians believe God created all of humanity and is the Creator of the universe. In this way they see themselves to be fellow workers in this struggle.
Two types of time
Zoroastrianism divides time into two types: weekly and daily. The former is considered sacred and the latter the period of the deceased. Zoroastrians believe the dead can have an effect on the living. These spirits can bring luck and prosperity or hardships and sickness. They offer offerings to these spirits in the form of wine, milk, pomegranates, quinces, and sometimes special animal sacrifices.
One God
Zoroastrianism refers to a religion that emphasizes one God. Although its beliefs are very similar to Christianity in many ways, Zoroastrianism's belief system does not hold the same universality. The Hebrew people were the first to develop the idea of one God over a thousand year before Zoroastrianism was established. For example, the prophet Isaiah spoke about Christ's virgin birth in 701 BC. This was a century before Zoroastrianism.
Purity
Zoroastrianism is a strong believer in purity. It refers a belief that Ahura Mazda has been created perfect and that we shouldn't defile it. This is what Zoroastrians believe in practice. They have avoided burial and cremation for centuries. Instead, they lay their dead bodies out at the Tower of Silence, where vultures ate them.
Goodness
Zoroastrianism believes that goodness is an important concept. Zarasthura (the founder of Zoroastrianism) taught his followers the threefold pathway. This path is analogous with the "law and love" in Christianity. It teaches the importance to make wise decisions based on God's intentions. Zoroastrianism, however, emphasizes goodness and not purely good. Its doctrines can be found in many different religions, despite its similarities to Christianity.