you identified the exact problem. developing a website with very inexperienced people? requirements very fluid from the customer (they know what they want when

you identified the exact problem. developing a website with very inexperienced people? requirements very fluid from the customer (they know what they want when they see it)? agile, as practiced today, is the way to go. building a defined system with performance requirements? with a budget? using staff that understands the technology? something else, is the way to go. in my experience, a short requirements exercise (say 10% of the expected project duration), followed by development iterations, is the way to go. how long are the iterations? between 2 weeks and 3 months. take time for design. have milestones where the system is functional and stakeholders can interact. but not continuously.