What is your sight fixed on? It says in this passage that we fix our eyes on what is unseen. How do we do that? If it is unseen then how can we actually see it?
Now faith is the substance of things hoped for, the evidence of things not seen (Hebrews 11:1).
It takes faith to see the unseen things. When it says "look" in verse 18 of 2nd Corinthians, in the original Greek it can be translated to "take heed", “look at” once, and “consider” once. Or even:
1 to look at, observe, contemplate.
2 to mark.
3 to fix one’s eyes upon, direct one’s attention to.
Even when we look at something with our physical eyes we can miss details or even look past things because our focus isn't adjusted so we can see what we need to. Do you need to adjust your focus? Are you looking too much at the physical and not on the eternal things?
It takes faith to do so. We need the faith to look at what God's intention and purposes are. We need the Holy Spirit to help us have proper Kingdom perspective rather than a worldly one.