User Interface Design is the process of designing the interfaces in software and your computer devices. It focuses on the looks and style of the interfaces.
It basically is a part of UX Design which deals with the overall user experience. Ranging from the button shapes to sliders used, this is spectrum of all the designs created for an effortless user experience.
It comprises of the visual text, the written text, images, the button displayed, entry field and every thing that is related to the user interaction. The UI Designers decides on what the application should look like and how will it be displayed.
Also adding to aesthetics along with the purpose of the application, it is the responsibility of designer to create a perfect blend of both adding every single element required for the same.
It equally affects the usability of any application. If the design is too complex or unresponsive, user would never return back to the same application and find an alternative to it instead. But if the design becomes seamless and graceful, giving a high user experience, this would be more preferred by the user.
The layout should be posted in such a way that it becomes more intruding and less tiring for the mass to get used to. As it is said “Time is Money”, application should be easy yet quick to respond for getting the most in less time. One way of this optimization ca be usability testing where a small prototype of the application would be created.
This prototype would be for the actual application and hence the feedback by the user will help them to rectify all the drawbacks of that design and give a better view on how to implement and what all need to be changed.