Research and iteration to find the most meaningful icon for a concept are crucial in design. The icon must immediately convey its purpose through affordance, meaning its ability to suggest its use. It should also fit into a coherent usage schema, allowing users to recognize and use it instinctively. Simplicity and readability at a minimum size of 16px are essential to ensure good visibility across various devices. The graphic style, whether outline or filled, must align with the overall interface style, ensuring visual coherence. Additionally, icons should be culturally appropriate and easily understandable by the target audience. Contrast and spacing around the icon also play a role in its clarity. In summary, a well-designed icon enhances the user experience and strengthens the interface's effectiveness.