Consider the following before you start writing TDDs:
- The technical design typically starts after the sign off of the functional design. It can also start early for a functional area where the requirements are clear.
- Engage the technical lead early on during functional designing to understand the functional requirements and flow.
- Plan brainstorming sessions among the team to discuss different solution ideas.
- Plan separate technical specs for integrations and data migration.
- Plan communications within the team to handle cross-functional designs.