verbs - What's the difference between the constructs [adverb] なる (naru) and [adverb] する (suru)?

For example, what makes 相手になる different from 相手にする. I know that 「～になる」 is to be/become something, and 「～をする」 is to do something, but what does each imply when used?

Answer

Suru is active and implies somebody does something, but naru is passive and implies something happens. For example:

暖かくする / atatakaku suru = make it warm
暖かくなる / atatakaku naru = get warm.