In Porter v. Singletary, 14 F.3d 554 (11th Cir. 1994), the Eleventh Circuit stated the following three-part analysis in considering a claim based on trial counsel's failure to investigate and present mitigating evidence:
First, it must be determined whether a reasonable investigation should have uncovered such mitigating evidence.
If so, then a determination must be made whether the failure to put this evidence before the jury was a tactical choice by trial counsel.
If so, such choice must be given a strong presumption of correctness, and the inquiry is generally at an end.
If the choice was not tactical and the performance was deficient, then it must be determined whether there is a reasonable probability that, but for counsel's unprofessional errors, the result of the proceeding would have been different. Id. at 557; accord Baxter v. Thomas, 45 F.3d 1501, 1513 (11th Cir. 1995); Blanco v. Singletary, 943 F.2d 1477, 1500 (11th Cir. 1991); cf. Rose, 675 So. 2d at 571 ("The failure to investigate and present available mitigating evidence is a relevant concern along with the reasons for not doing so.").
Obviously, you cannot make strategic decisions until and unless you are knowledgeable about the law that controls and have sufficiently investigated the facts.