How to understand the effective defense in criminal cases

I understand that an effective defense in criminal cases refers to a defense that is targeted, legal and can play a practical role. For example, a case is really guilty, but lawyers have to defend innocence, and finally they can't achieve the real innocence effect. That's not an effective defense. This is just a formality. What is really effective should be able to. Provide corresponding evidence to support, and do not distort the facts. It respects the case itself. Therefore, when making a plea, we should consider whether it is a plea of innocence or a plea of lightness. Or any other direction? Only by determining the train of thought can we achieve the real defensive effect.