1. There is no such thing as a research project without dead ends.
2. Don't be surprised when your findings turn out to be...surprising.
3. The past tends to be inconvenient.
4. Light bulbs can go off even when you're reading a scholar whose approach you find utterly uncongenial.
5. If the literary work doesn't behave as your theory of choice tells you it should, then by all means, say so. Nobody brought literary theory down from the mountain.