SketchUp is a 3D modeling software for Windows and MacOS X that is very intuitive to use but still has a very decent range of functions. I aims mainly for architural application, but is easily extendable through Ruby scripting, and a vast range of ready-made extensions exist for download, many of them for free. There is also a vast range of ready-made models available in their "3D Warehouse"; users are invited to add their own models.
SketchUp was first developed in 2006 and got a wide distribution when it was acquired by Google and made available as free software under the name "Google SketchUp". In 2012 the software was acquired by Trimble; there is still a free (web-based) version, but today the main branch is SketchUp Pro, a commercial software that includes a Layout utility to create PDF presentations from the 3D models, plus other utilities.
My experience with SketchUp is mainly from the 2013 to 2017 versions, I have used it seldom after that. With that caveat, here are some techniques I found useful at the time: