Please research the terms 'User Interface' related to website applications.
A UI designer, designs each page layout which a user interacts ensuring that the UI visually communicates the path that a UX designer has laid out.
You should know your users, stay consistant, identify patterns and use visual hierarchy.
Please research the terms 'User Experience' related to website applications.
UX designers deal with the flow and "feel" a web page should have. Such as Develop and maintain design wireframes, mockups, and specifications as needed.
You need to know, Strategy & Content, Wireframing & Prototyping, Visual Design and Metrics & Analytics.