Jaycel never got anything via physical mail, everything came via email so - IMHO, the most important thing you can do is this:
Two to three weeks after USCIS changes the case status of the I-129F to. "Case Has Been Sent To The Department Of State", the petitioner should make an inquiry to the NVC via their public inquiry webpage (I'll link it below) and request the DoS Case Number for your case. At this point, they likely will not have it yet which is fine. The purpose of this inquiry is really to make sure they have both of your correct email addresses. The way you do this is to word the inquiry something like this,
"USCIS has notified me that they have sent my approved I-129F petition to you for processing. Attached to this request is a copy of my I-797C Approval Notice. I would like to request my Department of State case number if it is available. Also, please update my and my beneficiary's email addresses as follows:
Petitioner's email: email1@email.com
Beneficiary's email: email2@email.com
Thank you"
We did this and Jaycel and I both got every email from NVC and from the Embassy without fail. Some were addressed to me and some to her but we both got every email.