the general idea is to have a great breadth of knowledge, yes, and use it when meeting somebody to dash from here to there... until you get to the topic with which you have depth, then lasso the conversation full-force into this topic (x), and talk about it at length, refusing to let go if you get anything at all back (continue to hold the other's attention). then repeat until mutual trust is established.
the effect is you construct yourself as a genius in the eyes of the other; make it appear arbitrary that the conversation landed on topic x, of which you knew plenty, rather than on topic y or z, of which you only know the most skeletal of bullet-points. they'll be under the impression that you know x, y, and z all in the depth that you displayed with x.
This is pretty much spot on. It helps to have the right kind of knowledge. Cursory knowledge of things one must know and then in-depth on certain obscurities. If you can quote at length from The Death of Ivan Illiych people will assume you have read War and Peace, thus eliminating the need for you to actually do so. And so on.
Poll
