What is the burden of establishing entitlement to relief?

The petitioner has the burden of establishing entitlement to relief and must do so by a preponderance of the evidence. (In re Sassounian (1995) 9 Cal.4th 535, 546, 37 Cal.Rptr.2d 446, 887 P.2d 527.) Thus, to successfully mount a collateral attack, the petitioner must overcome the presumptions favoring the "`truth, accuracy, and fairness of the conviction and sentence.'" (People v. Duvall (1995) 9 Cal.4th 464, 474, 37 Cal.Rptr.2d 259, 886 P.2d 1252.)