as far as i understand, to get the conjugate acid of a base, take away a H+. to get conjugate base of an acid, give it a H+ cos H+ is essentially another name for a proton. and acids are proton donors.
Note that H<sub>3</sub>O<sup>+</sup> / OH<sup>-</sup> is NOT a conjugate pair, as the species differ by two protons. Although these species are both conjugates of water, they are not conjugates of one another.
I'm not a capital T teacher (in the NSW Dept of Ed sense), but I am a Chemist. I've also done lots of HSC tutoring, and know the syllabus almost backwards.