How to Improve Guitar Tone
A key element that distinguishes various guitarists from one another is the tone that they produce when they play. With some of the best players you can tell who it is by hearing just a few, or even one note (Jeff Beck, Eric Johnson and Wes Montgomery come to mind). Initially, new guitar players try to emulate the sound of their favorite players by focusing on what kind of guitar, amp, pedals, or pickups they use. These are all important but I am here to tell you, after years of experience, that the simplest and arguably best way to improve guitar tone is through your choice of a pick or the decision to not even use a pick at all.
I heard it once said that the "artist is in the right hand". What this means is that the right hand is primarily responsible for setting the string into motion; bringing it to life. The texture, weight, and flexibility of the material that comes into contact with the string to make this happen are all critical to the sound that is produced. Of course what "good tone" sounds like is subjective and depends on the context of the music you are playing.
In the context of rock, metal, jazz and blues what I have found is:
Heavier picks sound better than thin picks. Thin picks tend to flex too much. This extra motion slows you down as the pick must bend back into place after each hit to a string. A heavy pick does not give way to the string as you pick hard or fast. Thin picks also seem to produce a clicking sound as the pick strikes the strings and generally produce a "thinner" tone.
The tip of the pick should be pointed but not too sharp. If it is too round it is difficult to get a clean articulation of the notes. If it is too sharp then the tone produced tends to have too much high-end and not enough mid-low frequencies, producing a thin brittle sound. I often fine tune the tip of my picks with grade #0000 steel wool.
The material matters. Picks are made from a variety of materials including: celluloid, nylon, acrylic, metal and stone. This is an area for experimentation. Compare the sounds of similar shaped picks made from different materials. You will be surprised at the results. For example some materials work better on a clean versus distorted sound.
Shape is a matter of personal preference and comfort and does not affect tone as much as the other aspects of the pick.
Many times the best tone is achieved using your finger or thumb.
Relative to other musical gear purchases picks are cheap so experiment and try out a bunch of them. A good place to start is the basic Fender heavy pick. My current favorite is the Dunlop Ultex Jazz III.
I hope you are able to use this information on how to improve guitar tone through your pick selection. If you would like to hear some of what I have discovered on my "tone quest" visit, http://www.curtisguitar.com/free-music/ to get a free download of two of my songs.