Building reusable components is a key aspect of developing with ReactJS. Here are some tips for building reusable components in ReactJS:

1)Start by identifying the common elements in your application that can be abstracted into a reusable component. These might include UI elements like buttons, forms, or navigation menus, or functional components like data tables or charts.

2)Break the component down into smaller, more specific pieces. For example, a button component might consist of a wrapper element and an inner element that handles the text and styling.

3)Define the interface for the component using props. Props are inputs to a component that allow you to customize its behavior and appearance. For example, you might define a button component with props for the text, color, and size of the button.

4)Make the component flexible by using default props and prop types. Default props allow you to specify default values for props in case they are not provided, while prop types ensure that the correct data types are passed to the component.

5)Use the component in your application by importing it and rendering it with the desired props.

6)Test the component to ensure that it works as expected and is free of bugs.

7)Consider the accessibility of the component. Make sure that the component is accessible to users with disabilities, and consider adding support for keyboard navigation and screen reader compatibility.

8)Use the "composition over inheritance" principle. This means that rather than building a complex component by inheriting from other components, you should aim to build smaller, more specific components that can be composed together to create more complex UI elements.

9)Use higher-order components (HOCs) to add reusable functionality to your components. HOCs are functions that take a component as an argument and return a new, enhanced component.

11)Document the component's props, usage, and examples. This will make it easier for others to use and understand the component, and will also serve as a reference for yourself when using the component in the future.