Discovered a powerful heuristic for track selection which helps you to find track combinations that “work” very well together. “Mixing in key” is a fairly popular method for track selection. Basically you want to find tracks that are “compatible” in a musical way. I’ve found that following the circle of fifths either clockwise or counterclockwise, always skipping 3, leads to some really astonishing results.

Here’s an experiment, using counter-clockwise circle of fifths traversal on the song keys. Note that some tracks end in a different key than they start, so you always have to take that into account.