So - to start - we ask for a chronological outline of events, copies of the documents that affect those events, and the names, addresses, telephone, fax numbers, and e-mail addresses of all people who know of, or may be affected by, the events set forth in your outline.
For example, in a business dispute we ask for all agreements (regardless of whether written or oral), letters, memos, e-mails, profit and loss statements, and any other thing that documents or even may just tend to document what happened. Please provide all there is. What seems unimportant may have a dramatic impact on the choice of the legal path to be followed.