In this section, we'll set our own theme for an individual (or global) plot. Let's begin by implementing the following steps:

1. Set up your theme, as follows:
   • Change the legend title and position.
   • Change the axes titles' colors and relative size (1.5). Using  text changes the colors of the axes titles and the legend text, but not the label text.
     
   • Change the axes labels' text sizes; use axis.text: (Note that if you want to change the x and y axes separately, you should use axis.text.x and axis.text.y.)

mytheme <- theme(text = element_text(color="Blue"), axis.text = element_text(size=12),axis.title = element_text(size = rel(1.5)))

2. Use your theme with an individual plot:

p2 <- p1+mytheme

(Click on zoom plot if it's not clear or is compressed in the canvas.)

3. You can also set it globally for all plots at the beginning of your code:

(theme_set(mytheme)). 

The plots with our theme are as follows:

The default colors aren't always the most appealing; you may therefore want to use a different palette, by using the commands scale_colour_brewer (), scale_fill_brewer, or scale_colour_manual() .