I usually listen to only one track in repeat (for about an hour), one that I'm very familiar with, so i don't get distracted by it (it may or not have vocals)

I've notice that by doing so i stay in the same mind frame all the time.

Also, it is good to choose a track that puts you in the right mind frame, examples: "Chicago" by Sufjan Stevens puts me in an optimistic and somehow upbeat state, "A Warm Place" by Nine Inch Niles puts me in a more introverted-deep thinking state