There are three well known places to get fashion,
you will see Male and Female Fashion NPC's.
City of Thousand Streams (1k city).
West Archosaur, around banker.
Southwest Archosaur, near Arena Manager.
At West Arch Seamstress is behind wall in Tailor's yard.
More accesible Seamstress (to buy dyes and dye clothes)
is in Southwest Arch and in 1k.