Complete the scatterplot sections of the data-visualization-exercises.Rmd file.
Claus Wilke talks about scatterplots in Chapter 12 of his book Fundamentals of Data Visualization. Michael Toth also has a long blog post about all of the ins and outs of making scatterplots in ggplot.
General ggplot2 Resources
To see ggplot2 in action, check out the ggplot2 flipbook by Gina Reynolds, which shows each step in building various plots. Both the R Graph Gallery and From Data to Viz show examples of plots and provide code to make them.
Two great books on the fundamentals of data visualization that include ggplot2 code are Fundamentals of Data Visualization by Claus Wilke and Data Visualization: A Practical Introduction by Kieran Healy.
Another good reference book is the R Graphics Cookbook by Winston Chang, which has “more than 150 recipes to help you generate high-quality graphs quickly, without having to comb through all the details of R’s graphing systems.”
Finally, I recommend you print out and keep the ggplot cheatsheet handy. I have one by my desk and use it all the time!