You probably know that you can use the "Split" button to split a track down the center into two tracks.
But did you know that you can precisely select the split point for the two tracks?
On either the top multi-track waveform display or the bottom single-track display, find the spot where you would like to split the track into two tracks. Then, right click on that spot. A pop-up menu will appear. Select "Split Track at Cursor," and the track will be split into two at the exact spot where you clicked!
Note that the track is split at the mouse cursor, not the playback cursor.
If you are not pleased with the split point, simply press the "Merge" button and the tracks will be recombined.
Using this tool, it is possible to very accurately split up tracks. It is especially useful for live music albums (or any album where one song fades directly into the next song) for which the auto track detection fails.
For more help, see the tutorial on splitting tracks