How did the shepherds praise Jesus?

Read the book of Luke chapter 2. Versus 8-20 in particular. If you really want to know, read those versus.

But here is the main verse that answers your question:

Verse 20: The shepherds returned, glorifying and praising God for all the things they had heard and seen, which were just as they had been told.

I still advise you to read the context.

~Prince Lion - A True Christian.

Source: Self-knowledge and the Holy Bible.