1. We must affirm that revelation occurs within history. That is essentially to say that the historical man Jesus Christ is the revelation of God, and therefore (note the logical order, which differs from the temporal) the OT history is the revelation of God. Secondarily, this means that the Scriptural accounts which purport to be historical refer to actual events - they are not myth, or edifying stories designed to convey religious truth. They record events which occurred in the usual way, in connection with other events, through the agency of people (including God) in the space-time universe in which we live.
2. We must deny that history is revelation. Although all the events of history are connected to the events of God's revelation, they are not all revelation themselves. We cannot therefore seek revelation in the history of religions, for example, or - as the older liberals sought to do - in the history of culture more generally. At the micro level, we cannot seek revelation in our own personal history either. This is, I think, what lies behind Barth's much maligned distinction between 'history' and 'sacred history'. The latter occurs within the former, and could be described as its inner logic and justification - but the two are not identical.
3. We need to think carefully about exegesis of Scripture. We can helpfully use information from general history to illuminate our understanding of the Bible, but I think we should be wary of allowing general history to become controlling. The Reformation assertion that Scripture interprets Scripture is to be maintained, albeit in a nuanced way.
4. We must avoid allowing history to judge revelation. Basically, I mean that the events of revelation, which take place within history, cannot be considered purely from a historical point of view. The rules of general history do not take account of the fact that God acts, and perhaps they ought not to. But given revelation, we have to acknowledge that here, in this series of events and supremely in this person, God has acted, and his actions cannot be explained within a general historical framework.
5. We should take care about using arguments from general history in apologetics. I say we should take care; I think we should use historical arguments. But perhaps the only way a historical argument will work is to point out that there is something here that cannot be explained within the framework of general history. In other words, we cannot act as if general history could provide or justify revelation. But we might be able to argue that general history reveals at its centre a hole - and into that hole we can present the gospel, the revelation of God in Jesus Christ.
Is there anything I haven't thought of?