The most common case that I testify on as a commercial real estate expert witness is the "Breach of Contract". This routine type of case may have many twists and turns so my advice to the legal community is to draft an outline for your clients that will serve as a log.
A log of events would be extremely helpful for me in documenting when the breach occurred and a time line of any correspondence between the parties. Of course, a clear description of the breach which should be in the words of the parties.
Since all breaches include mitigation of damages, a time line from the client is imperative. If an attorney represents the owner of the real estate, then please have them provide bids from a minimum of two contractors and the commencement date of the refurbishment. Since it is a requirement of the real estate owner to market property, obtain a report from a broker, pricing that will move the property in the shortest period of time. Also, it is critical that I receive a CV from the broker and his experience within the geographical area.
The items mentioned above will "expedite" my review of all materials and will obviously assist me in substantiating my opinions. Therefore, the expense of a commercial real estate expert will be reduced.