Tradition holds that there are 613 guidelines by which Jews are to live, the Hebrew word for these guidelines is 'mitzvah' (singular) | 'mitzvot' (plural).
It very much depends on what sect of Judaism you relate to. Reform Judaism is more relaxed in terms of things like keeping kosher, fasting on yom kippur, mixed faith marriages etc. where as Orthodox...
Jews cannot eat Non-Kosher food. They have to wear skull caps, if they are orthodox. We cannot write, use electricity, or drive, on The Sabbath. (The Sabbath is on Friday night, till Saturday night,...