When adjusting audio levels, keyframe values, or edit points simply clicking and dragging on the appropriate graphical element will make a change. The value of the selected parameter will change according to how far the mouse is dragged. In most cases the default 1 to 1 sensitivity of this change will be fine, but this can be modified.
Figure 1 The Command Key
In cases where you require a more subtle adjustment than the default sensitivity to mouse movement will allow, pressing the Command modifier key while clicking and dragging on a graphical control will result in much smaller changes. This modifier key will work with any click and drag parameter change. See the examples below:
Figure 2 Performing a Roll edit with the Command key modifier. Notice how the edit point lags behind the cursor, indicating slower movement.
Figure 3 Bringing down the audio level of the "Mahaiy" clip to -15 dB by clicking and dragging on the red audio Clip Overlay
Figure 4 Adjusting the Keyframe of a Video Filter by clicking and dragging on a Keyframe