How to change the font sizes in Gnuplot

How to change the font sizes of labels (x and y axis) and keys for Gnuplot? The default fonts turn to be too small when I shrink the images in my paper.

Several methods are available for Gnuplot:

Set the global fonts size for the terminal:

set terminal enhanced font 'Verdana,10'

Here, 10 is the font size.

Set the key fonts:

set key font ",10"

Here, 10 is the font size.

Set the fonts for labels of x- and y-axis:

set xtics font "Verdana,10" 

Here, 10 is the font size.