Years ago I felt that I had fallen into a hopeless rut with my acrylic painting. One day while I was in the public library I noticed an old issue of The Artists magazine. The cover article was titled, Capturing Realism in Oils.
This article basically laid out the technique and formulas that the Renaissance master Titian used. I was so impressed by this that I went home and threw away my acrylics, then bought all the materials that Titian used.