The form of Keats' "On the Sea" quite literally mimics the appearance of the sea.
The structure of the lines mimics the formation of waves. Thanks to the way the lines are indented, the poem appears to undulate, much like the waves of the sea.
In this poem, the poem's structure and subject matter are intertwined.
Persuasive Devices - Think debates. People will use the art of persuasion to make their ideas appealing to the audience. It applies the same way here. The author will use persuasive devices to make their ideas known to the reader and make them appealing.
First person view is the view point of the character writing or speaking directly about themselves. Third person view is the author or narrator telling the story. One advantage for First person would be that you can hear or read the thoughts the characters or having. A disadvantage in third person view is you can't know what the characters are thinking only their actions and what they say.