If you are stuck doing something in R, the quickest way to find help, is to get information on the functions that you are using from R itself. For instance, if you want to know more about ggplot’s histograms, you can type
?geom_histogram. This will give you the minimial information in order to understand the function. I find the information provided by R rather difficult to read at times, so I’ll typically use google. The ‘official’ ggplot-pages are incredibly helpful: http://ggplot2.tidyverse.org/reference/geom_histogram.html.
The stackoverflow-pages are also very helpful, because they present problems that people have had and their solutions. Nine times out of ten, you’re not the first who came across a particular problem. For example: https://stackoverflow.com/questions/21027548/cropping-extra-white-space-in-a-plot-made-using-ggplot-package-in-r
As we’ve seen, the cheatsheets provided by RStudio are also very helpful (https://www.rstudio.com/resources/cheatsheets/).
I also recommend the following books:
Chang, Winston. 2012. R-Graphics Cookbook. 1st ed. California, US: O’Reilly Media. http://www.cookbook-r.com.
Garrett Grolemund, Hadley Wickham &. 2017. R for Data Science. 1st ed. California, US: O’Reilly Media. http://r4ds.had.co.nz.
Healy, Kieran. 2018. Data Visualization for Social Science: A Practical Introduction with R and Ggplot2. 1st ed. world: the internet. http://socviz.co/.
Wickham, Hadley. 2016. Ggplot2: Elegant Graphics for Data Analysis. 2nd ed. Cham, Switzerland: Springer International Publishing. http://www.springer.com/br/book/9780387981413.