The order of the tracks on your CD could have a significant effect on your sales figures. How so, since no-one who buys the CD will care much about the order at the time they decide to buy?
Let's go back for a moment to the days of vinyl. Back then, an album lasted around forty minutes – twenty minutes on each side. You might not have experienced this, or I'll bet you have forgotten, but in the days of vinyl albums it was very common only to play one side at a time. So you would pick an album, decide which side to play, play it, then pick another album. So the role of the album was to give you just twenty minutes of pleasure at a time, but either side had to give you equal pleasure.
So it became commonplace to start each side with a great track, and since the band or artist only needed to fill forty minutes, there weren't all that many tracks so all of them could be at least good.
Now with CD, people's expectations have changed. Since the CD format can accommodate up to 74 minutes as standard, it started to become accepted practice that an album should last over an hour. And since CDs only have one side, that is an hour without any obvious break.
So when you put on a CD, there is no choice of which side to play, and few people would ever think to start from, say, track 10. Now answer the question on how you should order the tracks.
It's a no-brainer – all the best tracks have to go right at the head of the CD. And once they're done, the rest of the tracks are set in order of decreasing quality. You'll put on a CD, enjoy the best tracks, then at some point become dissatisfied with what you are hearing, take off the CD and put on another. There is no longer any concept of taking the listener on some kind of musical journey. Just the few best tracks followed by the mediocre followed by the downright bad.
The advantage in terms of marketing to have all the good tracks early on is because often the CD will be played in company. People who haven't bought the CD yet will say, “I like it” based on the first two or three tracks. They will then go out an buy it little suspecting that it's not all up to the same standard.
It's little wonder that the single track has become the norm for music downloads.