The more volume a studio takes on, the higher the odds of human error: a link copy-pasted to the wrong client, a mislabelled retouching folder, a delivery sent twice. It's never a matter of skill, it's a matter of system.
A naming convention, non-negotiable
Client name, date, type of session: every project folder follows the same structure, no exceptions, even under deadline pressure. That's the baseline that heads off 90% of cross-delivery mistakes.
One delivery per project, never a generic reused link
Never reuse the same link or the same page for two different clients, not even for convenience. Every delivery has to be its own object, with its own record of who opened, downloaded and approved it.
On xFer, each delivery is a standalone page with its own link and its own tracking: there's no way one client lands on another project's files, unlike a poorly partitioned shared cloud folder.
A dashboard, not your memory
Past three or four active deliveries, memory no longer cuts it. Keep an up-to-date list (a spreadsheet or a dedicated tool) of every delivery in flight, when it was sent and whether it's been approved. The day a client asks "where's my delivery at?", you answer in ten seconds instead of digging through your inbox.
In short
A strict naming convention, a separate delivery per project, and centralised tracking of every active delivery. Volume only becomes a problem when your organisation can't keep up with it.