Start with the whole picture.
A transformation rarely has a single starting point.
There is usually a business challenge, an organisational issue, a process that no longer works well, a technology opportunity — and often several of these at the same time.
I like to step back and understand the whole picture before deciding what the solution should look like.
What are we really trying to achieve, why does it matter, who is affected, what are the opportunities, and what would success actually look like?
Only then do I want to start deciding what needs to change.