As soon as you begin, you realize that it isn’t as easy as you thought it would be to produce a clear sound on a violin. Because the violin is sensitive to the amount of pressure applied, the speed of the bow, and the exact placement of the bow on the strings, it is easy to produce a scratchy or weak sound even when trying your best. Instead of attempting to play tunes, try focusing all of your attention on simply drawing the bow across an open string. Observe the bow as you draw it across the string and try to keep it as parallel to the bridge as possible throughout the entire bow stroke. If the pitch begins to fluctuate or the sound breaks, stop and try again instead of continuing to play. You will gain more control this way than you will by continuing to play with a questionable sound.
The key to tone production is the balance between bow weight and speed. If the bow is pressed too hard and moved too slowly, the tone will be scratchy; if it is too light and fast, it will be flutelike. Try playing long strokes from the frog to the tip of the bow and notice when the tone becomes full. It may help to think of the tone flowing out of the fiddle, rather than being pulled across it. Keep your fingers flexible; this allows the bow to nestle into the string. If your hand is stiff, you will be pushing the bow, causing it to slide or bounce across the strings, even if your arm is moving correctly.
Perhaps the most frequent error is the bow sliding toward the fingerboard as you bow out. This is due to the elbow lowering and wrist locking toward the end of the stroke. You get a fuzzy sound which seems beyond your control. You can help yourself by practicing in front of a mirror to see if the bow stays in the same lane between the bridge and the fingerboard. If it doesn’t, just raise the elbow a hair more, and don’t lock the wrist. A little bit helps.
Doing a small amount of work every day is better than none at all. If you can practice your open strings for about 15 minutes a day, splitting your time as evenly as you can between all the strings (not just your favorites), starting with long bows and decreasing their length while maintaining the same tone, and ending with alternating bows on adjacent strings to practice changing strings, you will be amazed at your progress even though the work seems so menial.
If frustration creeps in, shrink the task rather than ditching it: try playing just the middle third of the bow where control is most manageable, or lighten up on the pressure until the sound becomes clear once more. The clear sound comes not from pressure but balance, and the balance comes from attention: the ear becomes more discerning, the arm more adept, and the violin finds its voice with far less effort than you’d imagine.