I feel like this question varies from town to town, depending on how the resources pan out; however, something I've found constructive is to make specific threads for each topic and each day, split up like so:
Day 5: Construction
Day 5: Scavenging
Day 5: Upgrade
Day 5: Expeditions
The construction thread should start out with your current defense and include the math for each viable upgrade (including total AP cost [including conversions] and total resulting defense upgrade). It should also spec out potential upgrades if certain resources are found on that day, and quickly determine how people should spend their AP if they must do so early in the day. Once general ideas are agreed upon, only a single response should be needed in the main construction thread.
I'm not sure if this is common practice or not, but I always start these in my towns and, minus some inevitable bickering, it usually works out with people, and then other people start picking it up and starting the threads on their own.
The expedition and/or scavenging thread could also include resources found during those searches, so builders can use that as a reference point for future construction. This data could also be posted in a
Day 5: Resources thread.
Hopefully this is helpful and not just redundant/obvious. =)