But seriously, I believe that the best strategy is to ask them first what are the charges and who are the witnesses against you. They might not have enough to make a JC against you; mMost people simply confess at their JC and the elders often rely on this. If you can convince them that you have no intention of confessing anything, you have a very strong chance of not getting into a JC at all.
If it is a hard evidence such as a photo, an email or anything else, you can still deny saying that the person who brought the proof to them fabricated it; thus, they will need to stand by the two witness rule.
Also, there is the question of how the other evidence(s) was obtained. You may explained to them that you will not accept that anyone invades your privacy and may ask them what they intend to do with the ones who obtained the information illegally. You will first take the steps described in Mathew. That is, talk with your brother, then talk with that brother and another witness and then, bring him to the elders if he still doesn't listen. If the situation cannot be contained within the congregation, you will have no other choice but to use the legal system as there is no way you will accept such violation of your privacy. Of course, you hope that the elders will do what is right and avoid all this as the entire process will be painful for everyone involved. And think of how this could bring reproof on Jehovah's name? You may also state that you would not one minute believe that the Elders, representing the watchtower, would condone illegal actions by using illegally obtained material in the course of their proceedings.
Keep in mind though that such arguments are to be brought BEFORE a JC. Otherwise, the elders will feel pressured to render a decision and that decision will not necessarily be based on logic.