Even in a small claims case, we strongly advise you consult with an attorney to craft your demand letter and discuss the procedures you need to go through:
sending the demand letter certified mail, return receipt requested
filing a small claims complaint at the court clerk's office with the filing fee (if the case remains unresolved)
hiring a process server to serve a copy of the demand letter on the defendant and obtain proof of service
serving a subpoena on witnesses to appear at the hearing date (if necessary)
answering any counterclaims
appearing at the court date on your behalf