Things to consider when designing the user interface

• Consider the whole user experience. Plan it step by step.
• Have a prominent search widget and a prominent filter widget.
• If something is unavailable, rather than taking it away and letting the user guess about whether or not it will be available, list it, indicate it is out of stock and let the user have the option of being alerted once it is in stock.
• If there is a location feature, allow the user to change location if necessary. 
• Allow users to clear filter and close panels easily.
• Give custom suggestions for search and let users view recent search
• Think of how to make the search experience better. 
• Ensure that the user has less need to remember things.
• Think about the questions that your user might need to answer to make a decision and help to provide it.
• Allow for comparison of products and allow users to bookmark things.
• Make editing easy. As the user keys in, the screen should scroll down to reveal the next box.
• Ask for permission only when needed, not at the beginning of app usage.
• Add short text labels and visual keys to aid comprehension.
• Make sign in seamless - you can use social media sign in.
• Good design and visuals put users in a delighted mood.
• Use white text on a coloured background. Avoid using contrasts that are too sharp as they are unnatural and jarring. Avoid pure black and pure white. 
• Use custom table cells that will animate when something is done to it. Keep animation short. Examples of animation is the shifting of the cells up when moved up or turning left when shifted left.
• Use analogous colour types.
• Use pictures, thumbnails, colours for easy recognition.
• Think of helping users to colour code or tag something easily.
• Minimise user steps.
• Be wary of clumsy user fingers. Think about what mistakes they could make and how they could rectify it easily.
• Think about the user's mental model? How would they expect to use the app? When will a process end? What is their goal state?