I have had nothing but good luck with Kijiji.
I post the items I am trying to sell. I clearly state PICK UP ONLY and give a general idea of where we live. When someone is interested I set up a time for them to come (when it is convenient for both of us) and view the item. I give them my husbands cell number only and tell them to call when they are leaving. If they do not call they are out of luck. LOL
Anytime someone asks if they can pick it up on a certain date, after viewing it I always have them sign a waiver and leave a deposit. It clearly states that they will pick the item up by such and such a date and if they do not then they forfeit the deposit and I am free to sell the item to another person.
Sometimes I have several people interested but I always give the first person first dibs. If we can not set up an agreed upon time to view the item I tell them I am offering the item to another person and they either a) make a point to come and see it asap or b) forget about trying to buy it.
Whatever you do just remember do what is convenient for you. Do not go out of your way to accommodate someone else beyond what you feel is reasonable and if you feel someone is dicking you around they probably are. I can generally tell by the contents of the email received.