Why not start in zbrush and use zremesher? Or start with a base model and sculpt from that (you could use Makehuman or some of the provided sculpt meshes to quickly get a mesh to start from). For some types of clothing if you want to save yourself some hassle maybe use MarvelousDesigner? Anything with folds and wrinkles…
@cryrid Is "Decimation Master" not really used in the industry? If so, why? Because you can't controll the flow? I know one person can't answer such a question alone, but i have to start somewhere :D that thing with the uvs... on this video " https://www.youtube.com/watch?v=ki0jBmjrqc4" at "00:40" he says "Work on clone…