Familiar with the idea that you could make your money work for you instead of the other way around? That’s the same principle behind passive link building. In essence, you don’t do much work to maintain anything. There’s just the barest and minimum amount of effort needed to keep things running smoothly.
This is, of course, ideal. After all, anything that you can do with the least amount of work that yields great results is worth learning about. Do more by doing less. It sounds like some ancient kung-fu type of discipline, but in a sense, it really is. So if you are indeed interested on how this can be achieved, here are several ways through which you could link build passively.