One of the main advancements is in the development of print: specifically, wood block printing. The use of woodblock printing itself in China dates back into the 3rd Century B.C.E, but the printing during this time was extremely intensive and required "as many as 1200 printing motions... to complete one meter of three coloured silk fabric" (most of the blocks from this time that have been discovered are made out of brass instead of wood).
In a text translated as the "Forest of Tang Anecdotes", there is a passage describing perhaps the creation of the predominant form of woodblock printing in the mid Tang dynasty during Xuanzong's reign. (Parentheses and quotation marks added for context and highlighting)
The emperor Xuanzong's Liu Jieyu (Jieyu being a title of an imperial concubine) was both able and educated, and the emperor set great store by her. Her younger sister, married to a Mr. Zhao, being of a quick-witted and intelligent disposition, told craftsmen to carve wood blocks into an intricate flower pattern, to make an image (a mirror image on another block), and create a "clamped resist". On the occasion of her elder sister's birthday, she presented a bolt of the resultant cloth to the Wang Empress, which the emperor saw and was impressed by, so that he ordered his palace staff to manufacture using her method. At that time [the method] was top secret, but gradually it got out, and spread about the land, so that even persons of no consequence at all wear [this cloth].
So, whereas before, in early times, transfer of dye to textile was first achieved by tying knots to exclude dye from the surface, and then stamp applied wax resists were used, with the account of Liu we see the origin of the use of blocks with patterns carved out in relief. This method was quicker than previous methods, and due to the wide spread of its use, we can see that it was considerably easier to adopt than previous methods.
Additional sources:
Chen, History of textile technology
Laumann, The secret of excellence in Ancient Chinese silks