Credibility before everything else
Most people instruct a solicitor at a moment of difficulty or significant decision, and they arrive at the website anxious and risk-averse. The first job of the site is to make them feel they are in safe, competent hands. That means visible credibility above the fold: the firm's regulatory status (SRA authorisation), named solicitors with their qualifications and areas of expertise, genuine client testimonials, relevant accreditations (Legal 500, Chambers, Lexcel, conveyancing quality schemes), and a professional, current design that signals a serious practice.
The common failure is an outdated or generic site that quietly undermines confidence — a firm trusted with a property purchase or a custody matter cannot afford a website that looks neglected. In law more than almost any sector, the medium is part of the message: the site's quality is read as a proxy for the firm's diligence.