How does music shuffle work?
Shuffle play is a mode of music playback in which songs are played in a randomized order that is decided upon for all tracks at once. It is commonly found on CD players, digital audio players and media player software.
Is shuffle play actually random?
As observed by LifeHacker, Spotify doesn't shuffle your songs entirely at random. Rather, it uses an algorithm to “blend” certain genres or songs together. Spotify tries to avoid shuffling songs that sound too dissimilar from each other.
How do I put my music on shuffle?
Press the shuffle button in the media controls. It looks like two interwoven arrows. It's on the opposite side fo the Spotify Repeat button, which is nice because the buttons are pretty tiny and it would be very annoying to constantly hit the wrong one.