Clamp indirect 4, filter glossy at .5ish, multi importance sampling on for lights but not for the scene unless you have a more complex global light source, disable reflective caustics, lower light bounces to around 5.
Use google a little more, there are a few good guides out there.
less lights… every light you adds more noise in a way. you kinda have to get a feel for the noise patterns cycles makes to understand what is going on and where the noise is coming from. but that takes time lol
tldr multiple importance sampling is a blessing and a curse
Search for things like Denoiser node trees, there are people sharing the blend files with those nodes in it. It will clean all your noise out of a low sample render… If you tell blender to render to multi channels in the paths option a compositing denoiser mode can then apply things like bilateral blur to every channel, this is way more effective than something like a noise reduction filter in photoshop on the final saved image.
Sounds complicated but look for a tutorial on it and it will become obvious and simple.