Literary devices are used Alliteration Rhyme and Repetation
"I got my ticket for the long way round"
"When I'm gone"
"You're gonna miss me" are Repetation. It is repeat the sentence. It can be seen that this song will be repeated this sentence. The first sentence mean preparation, buying tickets for the long journey. The second sentence and the third sentence means to say about that when I'm not with you, you will think of me, think of everything about me.