I think that text is pretty good as an introduction to things - anyway now that I think of it I guess one shouldr really think of the defining properties of stacks as being able to glue isomorphisms together when you have isomorphisms locally (w.r.t. your grothendieck topology) from a thing to another and be able to glue objects together - both of which seems pretty intuitive to me

amybe im just restating things you already know though