Maybe the principles could be listed:
1. Atheists cannot win a contest against actual disciplined logic.I have sometimes kept a list of issues which a particular Atheist has dodged, and then presented it to him. Sometimes the Atheist will claim to have answered every issue, so I go through that again and again if necessary. Sometimes the Atheists will charge "gishing" and will run for the door. Either way, it is the observer who counts, not the particular Atheist. Don't allow dodging or off ramps: stay on point.
2. Generally Atheists use rhetoric, rather than logic; their goal is to "win", not to elucidate.
3. Always "play to the stands", meaning that the actual target is those who are watching and might yet have an open mind. With that in mind, there is no need for anger or dismay: the audience will understand the attack on you and why it is irrational, especially if you point it out calmly.
4. Never expect an Atheist to be convicted by logic; Atheism is an emotional decision and is not influenced by logic.
5. The Atheist is just an unwitting foil in the demonstration of the irrationality of Atheism. Expect nothing of him but irrational attacks, because that is what you will get served up. So prepare to demonstrate to the audience what the Atheist is doing, in terms of calm logical analysis of his claims and attacks. If there is no audience (the stands are empty), there is no point in even talking to an Atheist.
6. Keep doing it as required.
7. Always keep in mind that the Atheist always "wins" a yelling match: that's his intent; he cannot "win" if his position is logically analyzed.
There are some arguments which circle around and around, and those should be ended, with the reason for ending it made clear, and the end brought about definitively and finally.
Learn the principles of rhetoric and be able to recognize the rhetorical tricks. I've been doing this awhile, and even so, I get caught out sometimes. But a quick correction of course always works.