When we began our otolith research laboratory, we found the website from Steve Campana's Otolith Research Laboratory at the Bedford Institute of Oceanograhy quite useful (http://www.bio.gc.ca/otoliths/index-eng.php). You will find much helpful information to answer your question. Good luck!
Waleed, you can also take an advanced course at our lab. From 1 to 2 weeks we'll teach you diferent protocols of extracting, mounting, sectioning, polishing and reading of several species.
If you are interested in please contact via email.