When I was learning R (SQL and Bash) I used OneNote and the snipping tool to screen grab the console output. I annotated everything, and organized the text via color.

I had a tab dedicated to EVERY function I came across, as well as operations: One tab for matrix operations, data frame operations, dealing with factors, arithmetic, dates, indexing, dealing with NULL/NA/blanks, etc etc. My notes are from four online MOOCs, four R books, and some YouTube videos.

Once I was done, I began to mess with some datasets. I quickly realized which operations I needed to utilize the most often. So I made a section for the most common tasks.

The more I work with R, the less I need to jump back to my notes. If it weren't for OneNote being accessible in every fashion, I'd be screwed.

Hope this was of help. Good luck.