I am a big advocate that artists should do workshops or even take lessons with private art teachers. Yes, you can teach yourself with youtube videos and even self-help books, but sometimes that extra eye or just being in a class with other artists can really benefit you. On your own, you can only push yourself to a certain extent and the growth is usually substantially slower.
Last year, I had the privilege to do a figure drawing class with Pauline Gutter and just a few things that she said I believe already made a difference and gave me a new perspective. I am lucky enough to have had the privilege to study art under amazing artists and the stories they tell and advice they gave still sticks with me. But yet, now that I know what I know I really wish I had saved up more money to take courses with as many possible teachers as possible.
This is also where it becomes extremely important to specialize in a specific direction. When you specialize it makes it much easier to find the right teachers. As well as, to master a specific set of skills because painting landscapes are different from painting portraits vice versa.