Assuming you use a low grip rather than a high (recurve) grip on the bow, try rotating your grip slightly so that you hold the bow a bit more from the side. This 1.) increases the bend in your bow arm, allowing the string to clear, and 2.) lets you control the bow better by increasing hand/bow contact...generally more effective for deadening vibration on a featherweight longbow, especially with the added sideweight of a bowquiver. Another benefit will be you'll notice the bow shoots quieter...a nice little 'thump'. I believe the result is popularly refered to as 'fun'.
Those who shoot or have learned to shoot Howard Hill style longbows can attest to the effectiveness of this type of grip for bow control and better shooting with light longbows. It applies to R/D bows just as well.