The complexity of modern web development requires developers to employ various CSS tricks to enhance design and functionality while maintaining cross-browser compatibility and reducing code redundancy. Key techniques include using CSS selectors for targeted styling, the DRY principle for combining similar styles, percentage values for responsive design, pseudo-elements like ::before and ::after for adding content, and CSS variables for consistent styling across a website. Additionally, understanding the use of position: absolute, the !important keyword, and advanced features such as conical gradients and shape-outside for text wrapping can significantly improve a developer's efficiency and the user experience of a web page. These strategies not only streamline the coding process but also help in creating visually appealing and accessible web designs that perform well across different devices and browsers.