Make your priorities clear so neither of you waste time on listings that don't fit your criteria
(if you're a buyer) or on unqualified buyers (if you're a seller).
Set working guidelines (regular times to view houses or show your home, for example).
Keeping all of your paperwork in one place will help you and your agent when you need them.
Buyers, that includes your checklist of what you want, listing notes and loan documents.
For sellers, that includes your listing contract, loan documents, inspection reports, and disclosures.