The main thing about creating a good API is that you have a good relationship and good communication with the consumers of that API. I've seen a lot of people

The main thing about creating a good API is that you have a good relationship and good communication with the consumers of that API. I've seen a lot of people making internal APIs inside companies treat it as another way to throw something over a wall. There's very little universal about a "good" API design. Even response time might not matter if your users aren't using it synchronously. Best way to make an API is to have a plan to support old versions, release something early, see what people make of it and incorporate their improvements. Worst way to make an API is to try and think of everything before you start - you will fail and you'll take a long time