new atheists

[stonedape]

You will be arguing with idiots, so they'll drag you down to their level and beat you with experience. So you may have to implement their metaphoric language and turn it against them. It's important that you establish moral common ground. Just be firm but diplomatic. Flank them with their own logic.
1 - we're just going through a phase, and we're just rebelling.
Free will is timeless. Every one was born with one and has it stolen by tricksters that want to break your spirit and serve the interests of oppression. You refuse to surrender your free will to the slavemasters that rule Islam.
2 - we are stupid, ignorant, naïve or mentally ill.
Tell them you are free. You liberated your soul from the ignorance and mental illness of the imaginary psychopath. Stupid or not, you can think for yourself and that's a start.
3 - we were never true believers
I can't speak for you, because I was never a true believer. Relate your personal experience to them. Discuss the principals taught in the Quran that are compatible with your morals and beliefs. Tell them about the abusive contradictions that are standing in the way of those morals.

Never forget, Allah lives in their mind and you do not have the ability to evict him. It's up to them.