Interpretation is both a science and an art. As a science it deals with words, how they are defined and what they mean contextually. As an art, interpretation focuses on weaving together an understanding of the whole work. Biblical interpretation requires the study of the original languages, of the text, of its historical and cultural background, and its literary structure. As an art, Biblical interpretation looks for patterns and themes; unifying threads that draw the Biblical narrative into a seamless whole.
A principle tenet of Biblical interpretation is that Scripture interprets Scripture. The Church Father Tertullian referred to this as the "analogy of faith." In other words, some passages of Scripture have plain meanings. These become the standards by which we understand more obscure passages. The clear interprets the less clear. Some people follow the reverse procedure, creating whole doctrines from an obscure word or phrase, and usually end up starting a cult in the middle of an American desert.
A good interpretive method emphasizes the unity of the Bible. The Old and New Testaments are not independent of each other. They offer the complete story of God's people. One of the chief proofs of this is the continuity of prophecy. Many Old Testament prophecies are fulfilled explicitly in the New Testament, and the original prophecies are almost always referenced specifically.
Equally crucial to remember is the fact that every passage of Scripture has meaning—even geneologies(!). Our postmodern culture often tempts us to write off things we don't understand. A common phrase is, "It doesn't mean anything, it just is." We can't afford to have this attitude toward the Bible. Our Lord Jesus taught us that “not one jot or tittle of Scripture will pass away until all is fulfilled” (Matt. 5:18). God inspired its authors to write everything they wrote for a reason. We must approach interpretive study expecting to find that meaning. Otherwise, the Bible may become a type of fairytale or an ethical guide, and not the powerful Word of God.