Instructions
Check reviews of the consignment store or instrument shop you are considering. Look out for any reviews that state the store did not pay the reviewer or did not make an honest effort to sell the items.
Take your instrument to an independent dealer for appraisal. Have any needed repairs completed before you take the instrument to the consignment shop.
Fill out any paperwork requested by the consignment shop. Bring the appraisal paperwork with you in order to negotiate a selling price if the consignment shop you use does not allow you to pick your price point.
Ensure the consignment paperwork describes your instrument in great detail. Take photographs of the instrument with the consignment ticket before leaving the store.
Check in with the consignment shop on a regular basis to inquire about the instrument. If you feel the store is not adequately trying to sell your instrument, drop by the shop unannounced and see if it is properly displayed and if the price you agreed upon has been changed.