The controlling case that has set the standard for ineffective assistance of counsel claims is Strickland v. Washington, 466 US 668 (1984). Strickland sets forth a two part test to determine whether your lawyer was effective:
Was your lawyer's performance deficient?
Did your lawyer's deficient performance cause you harm?
So if you want to determine whether your lawyer was effective, first you ask to ask whether his performance was deficient. One way that courts determine whether a lawyer's performance was deficient is by asking did he makes mistakes that were glaring, ridiculous and unprofessional? In order to prove that any mistakes made by counsel were glaring, ridiculous, and totally unprofessional, it is necessary to overcome a strong presumption on the part of the courts in favor of the attorney's conduct. The court will look at the case in the light most favorable to the attorney. Do not fall into the trap of thinking that because your attorney did something that another attorney did not do, means that your attorney was “ineffective” under the definition of Strickland. That reasoning is flawed and is likely fail.
Finally, even after you've determined that your lawyer's performance was deficient, you must ask whether your attorney's deficient performance harmed you. This is actually the most difficult part. If the evidence against you was overwhelming, a court will often simply say that even though your lawyer was ineffective, it did not make a difference at your trial.