Looking for some advice... I have a Seamaster Planet Ocean Big Size (black dial, steel bracelet , orange 12, 6,9 ) that I purchased new in May 2011. I have the box and papers. If the bracelet and case get polished it will be in "like new" condition. If I sell it what would be my best option to get the most $?
Take very detailed photos of it, the better the photography the easier the sell, describe it accurately and list for what you think a fair market price is on a forum or the like along with your sale terms. You will likely try to get scammed along the way by someone wanting you to ship internationally, make sure you insist on the safest payment method possible, and CONFIRM payment yourself independently, do not trust any email you receive saying you've been paid. Once you know for a fact you have the funds, ship via FedEX or Express Mail with tracking, ideally with insurance.
Maybe Ash's post (expanded) could be added as a separate sticky in the watch sale section. How To Sell A Watch
Interestingly enough I believe Craigslist can be one of the best places to sell a watch. Photos don't need to be that great, nor does the description really need to be that good. What needs to be emphasized in a Craigslist sale is that the transaction will only be done at an agreed upon jewelry store for the safety of the buyer and seller where the buyer is free to have the watch professionally inspected to guarantee it is authentic and in good working order. Craigslist works well for well known commonly faked widely desired watches like the Planet Ocean. I bought my Daytona off an IWJG dealer who listed the watch on Craigslist. FWIW.
NOT good for international sales, because precious metals and jewelry including watches are specifically excluded from insurance coverage and transport via Express Mail. The clerk will be happy to sell you the insurance coverage, but it is worthless for international shipments. Also if accepting payment by PayPal you must be able to provide an online verifiable signature (not just confirmation of delivery), this is NOT available for USPS Express Mail for international destinations. FedEx with insurance from a broker like Parcel Pro is highly recommended for international sales.