For example, let's look at Amazon. The target market is shoppers. Amazon sells a lot of things to a lot of different people of different gender, age, profession, demographic, ...etc. The challenge here is that the target market is not very well defined. So from a design perspective, the need to prioritise which design discipline sequence should be considered is crucial. So, the question here comes back to what is the most important 'scenario' for a user? Is the purchasing scenario, or maybe the searching scenario, could it be the content display or maybe the interaction options available? You will find that designers will decide on what they believe or have researched to be the most important user scenario based on a sequence of criteria, which is often referred to as "the narrative". It is the story of how the user will 'experience' the environment to ensure the best outcome.
In summary, as a designer you may want to
- Ask yourself what are the most important aspects the user cannot live without? What are the user expectations when they visit such an environment?
- Prioritise these aspects and expectations as criteria for your design approach
- Ensure that these criteria are well addressed from an informational design, user interface design and visual design perspective.
- Field test a beta version. It is important you capture as much feedback as you can to qualify your "design assumptions" towards your set criteria.
- Consider the feedback carefully and qualify/quantify it against the set criteria.
Good luck with your design approach.