What factors do you consider when making alterations that the customer requests?

Using technical language to answer this question is acceptable and even desirable because you want to demonstrate your technical expertise. Attention to detail is important here. However, don't throw in jargon just for the sake of it.

Example Answer: "I would take into consideration what the client wants first and foremost. How does she want to appear? If he is short, does he want to appear tall? If she is slender, does she want to appear curvy? For example, if a man is short, and he wishes to appear tall, I would hem his trousers with a slight break."