How to determine the size of market?

If you are a company, then:

Size of your market is broadly determined by the product you choose and usually as broad as possible. For example if you are coca-cola then you are in the drinks market and your potential market size of the market is everyone that drinks soft drinks (obviously babies will not be your market). You then narrow down the market and segment your market accordingly.

Once you have determined the size of your market, you can then focus on the growth of the segments and redefine your market.

There are many ways to determine product range, on new product development you might do marketing research, focus group interviews and also market estimates.

Customer awareness is really just trying to bring the products to the customers. For example TV commercials and advertising are the most common forms of getting customers to aware of the product offering

Hope it helps