personally i dont like bidding, why waste time, do you make alot more? just state the price you are comfortable to sell without loosing much, then when you realised that the demand not strong, you may drop abit to close the deal. Bidding also wasting time that you have to watch over the bids, for me, if the deal is to bid, i usually give it a miss. or i state my price i feel i can afford.
also, i usually response to the first sms or call, to be fair to the buyer in potential. even it has to wait for another day or two to close deal. of cos must have mutual trust.
last, be honest to the item you sell, a promise is a promise, matained your reputation, you can make alot of friends from the BnS too.
you will learnt alot when meeting ppls, from bad experience to good one that can even arrange for coffee session.