I recently took a 2-day workshop with Abbey Ryan and excellent still life painter.  She is the most meticulous and careful painter I have ever seen work.  Every stroke has purpose and achieves an effect.  I was able to do 2 still life paints from that workshop that I believe are quite good. 
She confirmed that I have a reasonable sense of composition for the still life paintings and I learned a great deal from her.  It was an overall excellent experience.  She will have a one day workshop in the fall at the Artists of Yardley and I am signed up for it already.