The ABCs of tone production are all interrelated. One cannot work without the other. The following gives a very broad description of each factor and how each relates to the other.
Contact Point: This is where you place the bow on the string in relation to the fingerboard and bridge. When you play closer to the bridge, the string gives you more resistance, producing a more penetrating sound. When you play closer to the fingerboard, your tone will be rounder and have a softer quality to it (I am not referring to volume, only tone), and the string will give you less resistance. Generally, as you play closer to the bridge, you will use less bow speed and more pressure. The opposite is true when you play closer to the fingerboard.
Bow Speed: This refers to the speed at which you move the bow when playing any given note. Generally, the faster you move the bow, the more sound you get. However, the pressure you apply to the string will also affect the volume as well as the tone. As I stated above, bow speed is also affected by the contact point.
Bow Pressure: This is the weight applied to the string from the arm through the bow. Generally, the more weight you apply, the louder the volume and the more penetrating the tone. However, the speed of the bow will significantly affect the resulting tone as well as the contact point, as described above.