In order to get your agent focused on looking at the properties that will most likely have motivated sellers, have him/her look at the comment section of the listing. Here are some buzz words that will indicate the seller may be motivated:
As Is
Fixer Upper
Handyman Special
Offer Fell Through
Vacant
Estate Sale
Relocation
Seller Lost Job
Divorce
Must Sell
Seller Desparate
Some agents will just send you every listing in the book, but if you ask them to limit the ones they send you to listings that mention one or more of these, you will have a better chance to make a deal.