Nothing. You need to know nothing to do art. No method or technique or style or anything else is required to do art. Art is big. It is too big to push into little boxes. I think it would be great to have a group of never did any art in their life people do some art. Art will find you. You don’t find it. You cannot tame it. If fact once you have tamed it becomes rote. I cannot tell you how many times I have forgotten this. This knowledge is almost like a vapor. Here to see and then gone as quick as it came. Selling paintings sort of gets in the way of doing art because when you sell something then you try and do it again. But you can’t. It won’t feel the same. Can you tame a wild lion? and if you manage to somewhat make him less wild , haven’t you killed him. No art is free. all you can do is make art everyday and wait for the wild animal to show up. When it does you have enriched the world with something only you could have done because you were where it was.