Many languages seem to use one word for "do" and "make", but I'm sure if you looked up the word for "do/make" in Portuguese you'd find two different definitions: one corresponding to "do" and the other corresponding to "make". There really isn't a single definition that covers both words that I can think of. "Make" is a synonym with "create". The only difference between "make" and "create" is that "make" is more informal. "Do" is a general word to describe an action. Verbs are sometimes called 'doing words'. Both are common words, and both are used in phrasal verbs, idiomatic expresses and grammatical constructions, so you'll find lots of exceptions to the rules above e.g. "to make a bed" doesn't mean "to construct a bed" (well, it CAN mean that). If you can't replace "make" with "create", then you're probably looking at a phrasal verb or idiom.