Trim to Start: Place your cursor at a point within an audio clip. Press a hot key and it trims the data from the start of the clip to where your cursor is.
Trim to End: Place your cursor at a point within an audio clip. Press a hot key and it trims the data from the end of the clip to where your cursor is.
Fade From Start: Place your cursor at a point within an audio clip. Press a hot key and it fades (in) the audio from the beginning of the clip to where your cursor is. You can pre-select your preference of fade curve.
Fade To End: Place your cursor at a point within an audio clip. Press a hot key and it fades (out) the audio from the end of the clip to where your cursor is. You can pre-select your preference of fade curve.
SONAR uses a click and drag operation and that is good as well but the key commands are much faster because you don't have to hover until an icon appears and lets you know you have engaged the SONAR editing command.