Keith Giffen has been a comic book stalwart for many years on many different books and characters, but his influence on me was largely related to his humor work. Ambush Bug, Justice League International, and Video Jack, just to name a few, were his books that I devoured as a teenager.
Aside from the fact that the comics he did were funny, I particularly liked Giffen's use of subjective camera angles, closeups, insert shots of elements, and pages with a large number of panels. The cumulative effect of all this was a rich and textured storytelling style that made me feel as if I could get lost in the world. In the stories in which he was the finisher (or penciller, anyway), the dark blobs of ink gave the world that these stories were in, despite that the plot might be chiefly concerned with a lost cannibalistic doll or a vicious giant koala that says "Nik Nak", a dark, brooding atmosphere that seemed to take the job of entertaining you somewhat seriously.
The number of closeups and the way that he sometimes used very small panels as establishing shots for a scene could be disorienting sometimes, but what it mainly did was force the reader to readjust his scale, and look more closely at the pages, the way one has to do with work like Tintin or From Hell. That sort of storytelling is the sort you can't hold at arm's length and absorb, but rather one that must be read one panel at a time, and one that has the capability of putting a surprise at the bottom of the page on occasion, not just on the overleaf.
Giffen primarily (in the stories that I read) did not script his own work, but rather plotted it out very tightly -- I presume by doing layouts -- and then giving the work to a talented wordsmith to cram full of jokes. The result, I feel, was very fluid and gave a great sense of flow and interdependence between the words and the pictures. J.M. DeMatteis and Robert Loren Fleming were particularly skilled in mixing with Giffen's occasionally loonball storytelling style.
I like to think that a great deal of my storytelling style and narrative aesthetic came from reading these comics, which, though not terribly similar to any of my work, nevertheless created an atmosphere that I strove to at least partially recreate.