The most important thing to understand is that in Judaism there is no "God for Jews". Unlike religions that developed contemporaneously (such as Pharaonic Egyptian Faiths, Assyrian religions, Early Mede Faiths and so on), Judaism does not have a God who represents the Interests of the Jewish People against other nations and people. Judaism has One God who rules over All Nations and All Peoples.
However, if I understand your question to mean, Why do Jews revere the One God, as described by Moses in Exodus 34:6-7? The answer is simple, but twofold. Firstly, according to Judaism, God is responsible for all Creation including the entirety of every Jew's life. For this kindness and majesty they revere him. Secondly, according to Judaism, God is responsible for all Meaning in the World and for giving the Jews a set of Laws by which they can achieve personal enlightenment and cleavage to God in the spiritual plane. For this the Jews revere him even more.
Jews believe in God the creator and in the Torah which God gave.
Jews pray to God
Yes, same God for also Christians and Jews.
Christians and Jews believe that there is one true God. Christians and Jews pray to the same God.
The Jews. (Though strictly speaking, Jews do not believe that God is Jewish or that God has any religion.)
Yes, religious Jews think about God and follow His teachings and instructions.
Jews pray to God.
Jews worship God in 3 ways: With prayer With study With deeds of kindness.
Jews believe in God.What about Jesus?In Judaism, Jesus was a regular human being who lived in olden times, and is not part of Jewish religious belief.See also the Related Links.Link: Why didn't the Jews believe in Jesus?Link: What do Jews believe about God?
Hitler's opinion of Jews had nothing to do with God, and the Holocaust had almost nothing to do with religion: the Nazis saw the Jews as Communists.
Yes, there are atheist Jews.
Jews don't have Gods. They have a God.