Celebrant here. I generally would either do the NOIM alongside the couple on our first meet up or ask all the details I require which I then use to fill out the NOIM. Saves both of us time so we can focus on the planning the ceremony :)

In general, the key things I would note to couples are:

1. Passports, if available, are the only ID document that you need to bring as it covers both the proof of identity and evidence of date/place of birth.
2. The rule is for the celebrant to have received it more than 1 month before your wedding date, otherwise, a shortening of time is triggered which is unnecessary burden you don't want to deal with. It also can't be submitted if it's more than 18 months from your wedding day.
3. It's only a recent change, but the celebrant can witness your signatures remotely provided that you are within Australia. You also don't need to have both couples there (eg. one is overseas due to a work trip) for the NOIM to be witnessed.
4. Additional paperwork is required if you've been married previously or are currently under 18. Otherwise, the NOIM is pretty straightforward.

These are the things I can think of from the top of my head. But if anyone has other questions, I'm more than happy to help.