There are a multitude of types of evidence: statements by parties, evidence via experts in a particular field, and demonstrative evidence, among many others.  Demonstrative evidence is often key to winning a particular case. 

Demonstrative evidence is diagrams, objects or photographs.  It is said a picture is worth a thousand words.  In many, many cases, a photograph taken at the time of an incident or shortly thereafter is of immense importance.  This is often key to showing a negligently maintained condition or property or the extent of damage to a car or bruising to an individual to demonstrate an injury to a particular area of the body.  In any event, this is a particular area in which a client can do very much to assist themselves in a successful claim.  Take a picture.  Take several pictures from close up and a distance.  Have a relative take a picture on or as soon after an accident as possible.  Attorneys should visit a scene after an accident to determine any changes in condition and obtain those same photographs, potential witness availability, etc.  that may be demonstrated by a visit to the scene.  In the absence of evidence from a client this is often a crucial first step in pursuing a claim successfully.      In summary, the best evidence to start many cases is a simple photograph taken by the client that preserves “evidentially” the key to winning a case years down the road and through the adversity of defense witnesses and lawyers.