1. Not understanding the user: One of the biggest mistakes that designers make is not understanding the user. It’s crucial to conduct user research and understand the needs, goals, and pain points of the user in order to create a design that is truly user-centered. Not understanding the user can lead to a design that is confusing, hard to use, and does not meet the user’s needs.
2. Ignoring accessibility: Another common mistake is ignoring accessibility. It’s important to ensure that the design is accessible to all users, including those with disabilities. This includes ensuring that the design is compatible with screen readers, providing alternate text for images, and ensuring that the design is usable with keyboard alone.
3. Overcomplicating the design: Sometimes designers get caught up in creating complex designs that are difficult to understand. A cluttered and overcomplicated design can be overwhelming to users and make it hard for them to find the information they need. It’s important to keep the design simple and minimalistic, with a clear hierarchy and easy-to-read typography.
4. Not considering responsive design: With the increasing use of mobile devices, it’s more important than ever to consider responsive design. A design that doesn’t look good or work well on a small screen can lead to a poor user experience. It’s important to make sure that the design is responsive and that it looks good and works well on all screen sizes.
5. Not testing the design: Another common mistake is not testing the design. It’s important to test the design with real users and gather feedback on its usability and effectiveness. This will help identify any issues that need to be addressed and ensure that the design is meeting the needs of the user.
6. Not being consistent with typography: One of the most common mistakes is not being consistent with typography. Choosing too many different typefaces, font sizes, and styles can make the design look cluttered and unprofessional. It’s essential to use a limited number of typefaces and styles, and to make sure that they are used consistently throughout the design.
7. Not making use of white space: White space, also called negative space, is the area around elements on a page. It’s important for designers to make use of white space to create a clean and uncluttered design. A lack of white space can make a design feel cramped and overwhelming.
8. Not paying attention to details: Sometimes designers become so focused on the big picture that they neglect the small details. It’s important to pay attention to the details in a design, as they can make a big difference in the overall look and feel of the design.

Avoiding these common mistakes can help designers create a design that is truly user-centered, accessible, and visually appealing. However, it’s important to remember that designing a website or application is a complex and challenging task, and that mistakes will inevitably happen. The key is to learn from these mistakes and to continuously strive to improve the design.

The main aspect of designing is that you are constantly learning and trying to improve. The more you design, the better you will get at it, and the less mistakes you will make. The key is to not give up and keep trying. And also to always keep in mind about the user, the accessibility, and the testing process to improve the design.