Learn to use the dplyr R package which helps you to solve the most common data manipulation challenges such as filtering, summarizing or sorting observations| Stats and R
In this post, I highlight the 10 most common errors in R and how to fix them. I also mention a couple of warnings (which are different than errors).| Stats and R
Learn how to create professional graphics and plots in R (histogram, barplot, boxplot, scatter plot, line plot, density plot, etc.) with the ggplot2 package| Stats and R