I first tried oils in December 2008 on a course with Tony Williams, SWAc . I am always amazed at Tony's work and was lucky enough to have his guidance all to myself for two days. Tony taught me a technique to paint a rapid transparent monochrome underpainting using a rag.
I use this approach sparingly now and use transparent brushwork to lay out the work. Increasingly, I find I am getting better results from alla prima work rather than from studio paintings which I frequently re-visit.