1) God's character never changes; therefore what distressed Him in the days of Isaiah still distresses Him today. And what He had to judge then, He cannot overlook now. Is there anything in your life you must confess and forsake? And what if you are not willing to do so? Will God be able to overlook it? Think about what you learned about God and His ways.
2) God is sovereign. He ruled over the nations in the days of Israel. Does He do the same today? What, then, can you know? How might your nation fit into all this?
3) Amos says God doesn't do anything without first revealing it to His servants, the prophets (Amos 3:7). Therefore, from studying Isaiah, what do you know with an absolute certainty is going to come to pass? If the prophecies regarding the first coming of Jesus Christ literally come to pass (and they did), won't the prophecies regarding His second coming be literally fulfilled? How, then, are you to live?