Within the Appellate and Trial Courts portion of the Washington State Courts website, there is a pair of useful links to appellate practice information that you should review if you are involved in an appeal. 

The first link is called Appellate Case Processing Guide and leads to a series of concise descriptions of the basic elements of an appeal.  The descriptions include an overview of the process, timeline notes where applicable, references to the appropriate Rules of Appellate Procedure, and links to sample forms.

The second link is called Brief Writing — Best Practices and leads to a list of tips for writing a persuasive brief.  The comments address both construction and style.