If you are trying to rent, what I have seen them request in cases of bad credit is either an additional month of security on top of the first, last and the original security (in essence, 4 months), or an additional co-signer on the lease.
In these cases, we've had to go after the rentals that have received little interest and try to hand over a written offer as soon as possible, especially when every one else has been giving verbal ones. You should avoid the properties that get multiple offers like the plague.
In essence, don't try to hide the fact, come right out and say it: "Hey, we've had some bad luck in the past, but in return, we're willing to do this..." and that could mean an extra month, another signer, or even additional rent.
The truth is always your best ally.
Good luck! ;)
Gloria Rodriguez de los Reyes
Avanti Way Realty