When working with R, I feel like a have decent repertoire of tools and tricks to tackle many everyday problems. Yet often, I realize I could have solved problems more elegantly. For example I read about classes and methods, but haven't crossed the river to use them finally. Most likely because my everday work does not require that. Still I feel my creativity is limited by the tools I can handle.
What is the starting point, respectively what would be a good strategy to get beyond somewhat-advanced / intermediate beginnger / data juggling level?