How to make long soup Chinese style?

I have looked everywhere online and in cookbooks to make the proper long soup or clear noodle soup that you find in most Chinese restaurants. Most recipes give you noodle broth soups filled with meat and veg, and I want to know how to make just clear noodle soup, its always so full of flavour, I knows you may have to buy maybe certain food flavour enhancers and if so I want to know where they are and where to buy them.