Indeed, a UX designer must have some knowledge about psychology. Because UX designers need to understand how a user interacts with the systems he/she creates.
There are some common guidelines for visual design which should always be known by anyone in the design business as they are the basics for everything.find out more
In design there are multiple different effects that can appear beside the design laws.find out more
Obviously as an UX designer it is not required to be a marketing expert. You do, however, need knowledge on that field, too, as this will also be part of the user experience.find out more
Another important field of UX is branding which is also based a lot on psychology.discover more