All 4 films use flat lighting (little shadow and creates an even and bright look) - common in silent film as it enables the audience to look around the frame and watch Keaton interact with his environment.
A lot of the two-reelers where shot outdoors during daylight hours, to make use of natural light - e.g. entirety of Cops shot outdoors, in studio lots and local L.A vicinity, which roots the surreal gags in real locations.
Keaton employs deep-focus to provide a sense of perspective and contribute to the humour, as we can see the gag developing in the background.
e.g. In One Week, the audience clearly sees the train in the background hurtling towards the house. In Cops, Keaton naps on the horse carriage while the city can be seen unfurling in the background - all showing Keaton's adeptness at using cinematic space to build up a gag.
Keaton's character often placed at the centre of the frame, giving clear symmetry that allows the audience once again to focus on how he interacts with the world around him - the camera is straight-on at eye-level, so no expressionist angels to distract from the action in the scene.
In the chase sequence in Cops, the camera stays static in long shot as the action take place clearly within the frame - camera movement used only to emphasise a gag e.g. in One Week where the camera mimics high winds and adds to the absurdity of the gag as the characters try not to get swept away.