nor is it honorable to search out matters that are too deep. NIV Proverbs 25:27
Based on my experience, I think that there is an inverse relationship of how many topics you cover in a debate to its effectiveness of changing minds. That seems counter-intuitive, I know. You would think/hope that you could just dump out the evidence, have your opponent add it all up, and then come to the obviously natural conclusion that they've been wrong the whole time! But, no, it doesn't work that way.
It can work that way for books, blogs, YouTube, etc., because they have all the time in the world to consider the data. But when you are in a debate, you are in a discussion. Dialog is key, and communication is essential, so you must press on without time for lengthy consideration. Given that you and your opponent will be coming from completely different world views, true communication is going to be difficult, because you will use your words differently.
So keep it simple. Focus on one or two points, or certainly no more than three. Inevitably in defense of a position, other points will emerge which are worthy of their own exploration, but don't*. The more you meander around, the more you just waste your time, because there is a good chance you are just talking past one another.
Instead, center on one or two points, and drive those through until you are absolutely sure that your opponent understands what you saying, even if they still disagree. In fact, expect them to still disagree with you. As mentioned in Tip #1, just because they disagree with you then, doesn't mean that there is no hope of them later coming around.
If your opponent protests, saying that you are ignoring his or her other arguments, just reply something to the effect that, while you are looking forward to discussing those points with them, you want to nail down the one or two points first before continuing on to others.
* There is an appropriate time to meander off topic, and we'll discuss that in the next Debate Tip.