Agree a sensible way to exchange work and discuss issues on a timely basis.
As a Subcontract Accountant there's nothing worse than being handed a job with missing information and errors then finding the manager concerned has vanished on a two week holiday and no-one else knows anything about the work. This wastes everyone's time.
Agree a price for the job and a timeframe.
Normally this will be a fixed price to provide a subcontract accountancy service rather than an hourly rate, both parties have certainty, you because you can budget and me because I can allocate my time accordingly.
Sign a sub-contract / Non disclosure agreement.
You then have peace of mind that your clients remain your clients and you are the only point of contact with them. Also this can cover the scope of work.
Assess the quality of the work you are handing over, your opening work, notes and the clients records.
This saves a lot of time and cuts down on phone calls, emails etc
Set up relevant access to your systems.
i.e. Xero, FreeAgent, BTC etc then agree who puts adjustments through to the records and whether they are reviewed by you first.