How to clear up storage on iPhone?

I have a 64 GB iPhone X and a few days ago it started telling me that I was out of storage. When I went into settings, it tells me that the system is taking up anywhere from 12 to 32 GB of storage. How do I clear off the system storage or at least make it much more manageable?

Hook up your phone to a computer and dump all the pictures and videos into your hard drive.

Alternatively, get a phone that is able to support micro SD cards.