Wireframes -
A website wireframe suggests structure of a website and relationship between pages. It is a simple line drawing which demarcates different regions in webpages. Wireframes are the first step to any interface design. Art work for any web application / user interface begins only after wireframe is approved by user / client.
Wireframe should include all important elements of the web application. Each element can be represented with simple shapes with label to represent the same.
General and most important elements of any website includes -

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User Interface Prototype -
User interface prototype is a mock up of web application which is build keeping focused goal in mind. UI Prototype represents basic ideas behind the UI, which is generally tested by client / target market.
UI Prototype is extremely essential as it helps designer / developer / Client to test and explore different ideas and communication. UI Prototype will generally be in form of HTML pages, once the prototype is finalized, development of application / system can continue from there.
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Storyboard -
User interface flow diagrams is called storyboard. Storyboard help brainstorm on fundamental usability and relationships between major user interface elements.
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Usability -
Usability means creating user-friendly / user-centered design environment. It is the ease at which user / potential customer can interact with web application and attain desired goal.
Market is expanding and potential customers have lot of choices to choose from. Usability here plays a very important role to retain customer’s interest in a website. Companies find the benefit of spending money and energy to research and develop user friendly product.
Usability can be refined by employing set of generalized users to test the system for its efficiency, observing their interactivity and updating the system based on observed notes.
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Website Layouts -
There are a whole lot of criteria for a website layout to be successful.
Few of them are listed below -