Communication is key
Lack of communication leads to developing multiple mock-ups, instead of concentrating on one. This increases the designer's workload and the possibility for errors due to his concentration on quantity. Many proposals are overwhelming to the client too, so the designer must lead him in the right direction, clearly communicating at every step of the design process. Only this way can quality be assured, because clients often don't understand web as a media very well and mistake the designer for their site's audience.
It's important to explain why a particular design decision is appropriate for the client's needs and visitors' expectations. Communication is two-way—if one part wouldn't step in, the whole project is at risk. Regular feedback from the client helps to uncover changing requirements and emerging needs. These requirements must be fully documented and can then serve as a bilateral contract.
Some clients can't explain very well in natural language what they expect from the designer. He must reveal himself the hidden, unsaid details. Sometimes, everything seems clear, the project is rapidly designed and developed to find out, that the specification was incomplete, which invalidates everything that has been done so far. Maintеnance costs are much higher than specification costs, so caution is required.
It's important to strike a balance between too much and too little communication. For example, meetings consume much time and prolong projects in the future. A predefined project schedule with clear milestones and deadlines gives the client the transparency he wants and encourages better communication. If both sides don't respect themselves and communicate rarely, the designer will be late and the client over budget, so the project may never be finished.