根据 and 按照 can both function as a preposition that can be translated as according to. I imagine that the translation does not capture the individual character of each term. What nuances do the two individual terms express and in what situation/context would you use one rather than the other?
根据 is more formal, and preferably used when speaking about doing something according to some serious guidelines. Like following a law.
按照 is less formal, and can be used when doing something according to some less serious guide. Like following a person's idea.