Learning from the masters was considered a common practice in the past. Museums would allow artists to visit with their art supplies and make copies of famous paintings.
In this way while you are painting you encounter similar problems with the ones faced by the artists and you can see the solution that the artist found to each problem. If you study enough these solutions will transparently become your guidelines to art creation.
So, I must admit that I’m still studying and I’m still learning. Over the years what I have done to improve the outcomes of this form of study is to try to alter some aspects of the artistic creation to generate more problems that the ones faced by the artist. An example is changing the type of paints used with a less versatile medium (e.g. switching to acrylics or pigments).