What measures does the council take to develop a harmonized national market for goods and services?
From the given context, it is not explicitly mentioned what specific measures the Goods and Services Tax Council takes to develop a harmonized national market for goods and services. However, it can be inferred that they aim to achieve this by guiding their functions with the need for a harmonised structure of goods and services tax (as stated in paragraph 6). They also determine their own procedures (paragraph 8) and make decisions by a majority vote (paragraph 9), which likely includes measures related to the development of a national market.