There are 2 important types of CDs that you can burn.
An Audio CD can only hold 74 or 80 minutes of audio
An MP3 CD can hold MP3s and it goes by file size, rather than length of audio. Instead of 80minutes, it holds, 700 Megabytes (MB) of music. The MP3 quality will determine how much audio will fit. In practice, it usually is 10 times more, ie: 80 minutes. The number of songs will be dependent on how large the songs are.
To burn an MP3 CD, click the "MP3 CD" radio button on the "Song List"
If you have a DVD burner, you can put in a recordable DVD and get up to 7 times more than on a CD recorder. (4.7 GB of space!)
If you are trying to squeeze more audio on a standard audio CD, you can trim the start and end of each song and cross fade between songs. This can free up 30 seconds on average depending on the severity of the edits.