Studying how the authors of scripture themselves interpreted and used scripture in their arguments should provide a normative framework for our own use of scripture. That is, if there is a "true" hermeneutic, certainly the divinely inspired authors of scripture would abide by it. In spite of a few cross references within the New Testament, the bulk of evidence in this inquiry comes in the form of quotations from the Old Testament. This is not always a straight-forward endeavor, so I will here provide a few observations about the task of studying the use of the OT in the NT. In the sermon on the mount, Jesus said:
You have heard that it was said, 'Love your neighbor' and 'hate your enemy.'
Here Jesus gave us something to think about: the first admonition is from scripture, the second is not. That is, finding and studying uses of the Old Testament in the New is not always easy nor clear-cut. Based on the formula which he had been using throughout the sermon on the mount, we should expect to see scripture quoted (which is partially the case). Still, we have to be careful not to allow the form to overly influence our understanding of the content. No doubt many scholars have embarked on fruitless missions to find "hate your enemy" in the scriptures. Revelation is another interesting case. It has zero direct quotes from scripture. Of course anyone who has read Revelation and is familiar with the Old Testament knows that there are dozens of allusions and references thereto. When approaching references, we must ask, "is this really a reference to the Old Testament?" The next step is of course to find the source of the quotation or reference. The New Testament writers had no chapters nor verses, but occasionally there are references to the specific book or collection (i.e. "the Prophet Isaiah" or "Moses").
My personal favorite is the author of Hebrews and his formula: "somebody said somewhere." There are places where quotations cannot be linked with a single passage. For example, when Jesus uses "son of man" to refer to himself, he could be referring to Ezekiel (where it is God's title for the prophet) or Daniel, where there is recorded a vision of one like a son of man (however Jesus eventually made his meaning clear). Moreover, there are lengthier repetitions of passages (for example in the Psalms or in the prophets). So it is not always clear which of the options is being referred to (though it does not always make a difference). And of course there is the most infamous citation in Mark 1:1 where the author invokes Isaiah and proceeds to quote a conflation of Malachi and Isaiah. So, the second question which must be asked in approaching references to the Old Testament is "which scripture is being referred to here?" More questions are coming.