Hinduism in its popular form (vedanta) is yet another type of Polytheism or Monotheism, Hindus believe that there are countless gods and goddesses but all are facets of one God. Now does that make sense? The Christian concept of the Holy Trinity doesn't make sense either. There's also something of an atheist tradition in Hinduism.  Are you confused?
Karma and caste
Hindus believe in reincarnation and karma. A serious problem with Hinduism is the Caste system which treats some people as inferior because Hindus believe they did wrong actions in past lives though there is no proof that these wrongs ever happened. Not all Hindus accept the caste system, some see caste as an aberration of original Hindu teachings.  India is growing economically much faster than North America or Europe. Fortunately the Caste system is weakening there as India will become far more influential in the future.
They also think that cows are a "sacred animal". Cows are shown special respect at least part of the time. 
A Hindu user's view on Hinduism
Hindus believe that there are countless Gods and Goddesses, who are reincarnations of one God.
Three Gods in particular are the origin of their pantheon. These are:
Brahma, the creator.
Vishnu, the preserver.
Shiva, the destroyer.
Each God and Goddess in the Hindu religion represent a different sect of life. Most Hindus have a Patron God, who they worship most frequently but not exclusively. Common methods of worship are shrines, the burning of incense and praying.