I don’t mention it often enough, but there are some powerful plugins for SketchUp. One of the more powerful ones is Vertex Tools. It is a paid plugin(free 30 day trial), but well worth it! In the video below, you can see how easy it is to level out terrain for a building pad for instance. The colors on the vertexes shows how much manipulation the vertex will receive. You can control how wide an area is affected or how powerful the change will be. It is what makes this a useful tool.