I don't believe that God is the author of confusion, so I don't believe in the many ways to interpret His Word.
I agree that God is not the author of confusion, we are. Only one interpretation is fully correct. The problem lies in knowing which one it is. That is why we have this discussion to begin with. How do we know what for an example Eph 1:4-5 really says? Here are a few ways to approach that:
1. Get to know Paul. Learn about Paul, who he was, what was his drive, his way of writing etc.
2. Read many chapters, and whole passages, don't try to find meaning to a few verses here and there without the bigger context.
3. Get to know the situation in the church that Paul is writing to. What is the purpose for each letter? What's its main points? What is it that needs to cleared up?
4. Use translation tools and compare different translations or even better, learn NT Greek.
5. Learn about the thinking of that time and place, it's culture
6. Read and learn about the earliest Church Fathers, how did they understand the scripture?
7. Get to know all Paul's letters and compare and use them to complement each other.
8. Get to know the gospels and get to know Jesus, find out how Paul's writings fit Jesus' teachings.
9. Read having your personal revelation of Jesus by the Holy Spirit in the back of your head.
10. Try to read what it really says without the lens of a doctrine.