As a start, why not read When the Cathedrals were White by LeCorbusier. It is his critique on new york skyscrapers, and dates from 1937 in its first french edition.  (first american english edition is 1947).  He disdained any sort of imagery in skyscrapers, and considered the new york ones 'too numerous and too small' if  i may paraphrase the great man.

The earliest new york skyscraper was built for Singer Sewing Machines and designed by Ernest Flagg, who trained at the Ecole des Beaux Arts.  This for many years was the tallest building in the world (about 40 storeys) and had a pronounced fin-de-siecle quality inspired by the works of Violet-le-duc especially with respect to the expression of steel and glass in the facade at the upper levels.  Generally this building followed the schema given by Louis Sullivan in his earlier essay 'the tall building artistically reconsidered' which proposed elevating urban tall buildings up to a height of 12 storeys (the maximum a hook and ladder fire truck could reach in those days) along the property boundary, and then provide offices for the elite on higher floors in a tower set back from the lower facades.   You ll see in the illustration that the imagery he used was 'eclectic' not sullivanesque....each tower has a 'crest' that evokes a certain style of architecture in his conceptual sketch.  To get the idea across, the tower had to have 'style', but for sullivan this style didn't much matter, or was interchangeable.

Finally, have a look at the Hugh Ferriss scheme for skyscraper setbacks from 1929 but applied retroactively to the new york zoning act of 1916.  There is no style, but the 'ziggurat' imagery is both highly suggestive and informed a generation of new york skyscrapers including the chrysler building, the rca building at rockefeller centre, and the empire state building.    After the war the setback principle was simplified to accommodate the same volume of office space in more rectangular envelopes.  This has been the prevalent way of conceiving tall buildings ever since, as a sort of object in space rather than something which engages a city at street level.

You have to know a lot about the culture of the time contemporary with the skyscraper or skyscrapers you want to study....the longer the period of consideration, the more you have to know!  For instance:

Diana Agrest wrote a very interesting poststructuralist interpretation of the Yamasaki world trade centre:  Diana I. Agrest: "Architectural Anagrams: The Symbolic Performance of Skyscrapers." Oppositions 11 (Winter 1977).

Thank you Stephen for the valuable information. Surely it will be a helpful answer for my thesis. Cheers mate!!!

no worries. For what it s worth, Louis Sullivan also attended the Ecole  des Beaux Arts in Paris, and did build an office building (without a tower) in the Bowery in New York. Whether he had any contact with Flagg or not i cannot say.