What 3 actions does Holmes take when he first visits Saxe-Coburg square? What is the reason behind each of these actions?

In The Red-Headed League, Sherlock Holmes is initially drawn into the mystery presented by Jabez Wilson, a pawn shop owner bestowed with a head of fiery red hair.  Wilson has an opportunity to make a tidy sum performing menial work.  Holmes uncovers a more sinister plot, that of a bank robbery led by Vincent Spaulding, a young apprentice at the shop.

Saxe-Coburg square is described as a dingy and shabby square in a less part of town.  Upon arrival Holmes' first act is to pause in front of Wilson's pawn shop and look it over.  Next he proceeds to walk up the street and "down again to the corner" looking at all the houses.  Finally he returns to the pawnbroker's door and thumbs his cane upon the walk.

The first action, the overview of the pawnbroker's shop is to further his knowledge of the client, Mr. Wilson.  Judging the paint, the exterior door, dimensions and overall character of the establishment he can gather any information on the story provided.  He may also note details about the place, such as a fresh coat of paint or new bolt where none should be.

His next action, walking and examining the other houses upon the street provides familiarity for the scene and context for the story.  He correctly deduces Mr. Wilson's pawn shop is not the intended target, but the bank next door.  The overview of the location provides Holmes with tremendous insight most people can demonstrate.  Holmes understand that any story might be the end (if the pawn shop was the target) or the beginning, with the it being just a piece in a larger puzzle.

Finally, Holmes pounds upon the pavement to test his theory.  He undoubtedly heard a hollow sound or one not consistent with is knowledge of London as a whole.  The unusual sound provided more insight into how the pawn shop was being used as a patsy to gain access to the bank.