To make furniture in Google SketchUp, you can follow a step-by-step process that involves creating a basic structure using geometric shapes and then refining it with more detailed elements. Firstly, start by drawing the outline or overall shape of your furniture piece using lines or rectangles. Then extrude those shapes to give them depth and volume. After that, you can add additional components like legs or arms by connecting shapes or using specific tools like push/pull to modify existing forms. Next, apply textures and materials to your model to give it a realistic appearance using either pre-existing options within SketchUp or importing custom textures if needed. Finally, you can add finishing touches like joinery details or decorative elements before rendering your design for visualization purposes or generating 2D plans for actual construction based on your model.