Here are the steps designers should take in order to define the target audience.
Investigate the audience. Dig up as many details as possible and be thorough in research. Make sure the investigation is clear, concise and easy to understand and communicate to others on the design and development team.
Organize the information which needs to be presented on the site based on findings.
Express the information to be presented based on the findings. Pay attention to terminology, presentation and methodology to ensure the information comes across as intended and appropriately for the audience.
Master the information and the expression of said information. Present it clearly and effectively to foster usability and achieve the goals set forth by the objectives.
The more details one has regarding the target audience of a website, the better off the designer is. This information will help a designer throughout the entire design process and is absolutely necessary to the success of a website. Over time, as the site ages and changes, the target definition may need to be revisited, and each time a major re-design or addition to the site is developed, it should be considered.