Gerard Chaliand, an international guerrilla warfare expert and friend, describes war as involving a combination of strategy, tactics and instinct. These ingredients are also necessary in legal work, especially for litigation and the resolution of disputes.
To develop a strategy or tactics it is best to find the most relevant and reliable facts. Otherwise you may rely purely on instincts.
Finding facts takes time, effort, energy and documentation. Facts are events, transactions or circumstances either seen, heard, experienced or documented. They are not opinion, suspicion, hearsay or rhetoric.
Here's an efficient way to group facts in disputes and litigation. Prepare a chronology of events. Create a table with three columns and lots of rows. In each row of the first column type the date for each event; if the date is uncertain indicate this. In the second column type a short form description of each event. In the third column, name or refer to the evidence for that event. It may be a conversation, an act, a failure to act, or a document (eg a letter, invoice, statement, or contract).