All the pages we develop are created first by a UX designer (most of the times). Sometimes the designs are created well before a project starts.
In my experience i have seen designers and developers commit these mistakes while designing.
1. Not thinking about the responsiveness
This one is most commonly known mistake. Designer creates a beautiful page, but when it came to client he hated it. The reason is designer is gonna have the best screen available and almost same case for the developer who codes it. But business people work of screens of different size and resolution.
If the desinger does not design for the various screens. It’s gonna look odd on smaller or bigger screens.
2. No design for empty state
This is also occurs most of the time. Designer gives you a good screen with all the data on it. But what to show when no data is available? An image? Some text ? Nothing?
3. No design for content overflow
It does not occur frequently but sometimes designer forgets to accomodate content overflow. For example, what if the the title of a card is too long, will it be shown? Hidden ? Clipped ? Or shown ellipsis?
You must design for the situations where content can overflow the component and handle by truncating/ showing pagination/hiding unnecessary details etc
4. No design for intermediate state – loading state
You know it. You should add this also. Maybe show a loader. Or a progress bar or a skeleton of the component to be loaded.
Last is communication, you need to communicate with the stakeholders and developers and make sure that the correct design is implemented.
If you have any more tips please feel to comment.