I am just going to post these here and just add a couple things.
Just remember. A panel is a single moment in time and a full page is normally just a few minutes. Keep your dialogue count down to around 140 words a page. Keep to these simple rules and you will be comicbook scripting.
From Stan Lee….

and then this little nugget from John Buscema’s…..

In fact… this little one pager Milk Run was scripted in the Buscema Way. (f)art by Mister Simmons