We use our alphabet for ordering English dicioanrys buy as far as I’m aware, the Chinese language doesn’t have an alphabet. So how are they ordered?
It depends.
There are ones ordered according to radical (the part in a character that signifies (mostly) the meaning, like tree, fish, heart, water, earth,… Those are not easy to use, because you must be able to identify the radical and the number of strokes of the remaining part of the character.
Others are ordered according to the pronunciation of the character (Pinyin or Zhuyin), like a, ai, an, ba, bo, … These are also not easy to use, because you must know the pronunciation.
There is a book that helps learners to identify more easily the character and its pronunciation: http://amzn.to/hwO6k6 - this book allows users to find Chinese characters based on their appearance alone, without knowing their pronunciation, radical or stroke count.