Once your song is finalized, close your eyes and listen to the song, many times.

Copy that song on your ipod, mobile, computer and keep listening to it on a loop. Until you become familiar with every beat, every word and every possible action in the song. 

Listen to music seriously, close your eyes, and try to understand the meaning, think about the situations and let your ideas flow. Be creative, note down your ideas, even the stupid ones.