Ward's brief Wikipedia entry is here and other links touching on his career are here and here.
As can be seen below, his 1920s style is similar to that of contemporary illustrators such as Dean Cornwell who painted in thick oils. As many other illustrators did, Ward altered his style and media to go along with changing illustration fashion. One result of this is that there is no distinctive Ward style.
Compare the 1920s illustrations by Ward below to this Cornwell.
Vignette format illustration was common for secondary story illustrations. The lead illustration might have conventional rectangular borders, but others in the same magazine piece or illustrations in later issues containing other parts of the same, continuing story might be vignetted.
This possibly unfinished illustration or study was made around the mid-1930s. Note that the green hat in the mirror is not that same shape as the one in the foreground.
Here we see a change to watercolor or perhaps colored inks.
An example of Ward's postwar work.