Becoming an IM

Many decently strong players aspire to become an international master. They see very clearly that the grandmaster title is most likely beyond them but the IM title is one they feel they could achieve, if only... It's this "if only" bit that gets in the way. If only... what? Do they need to study the openings more? Should they focus on improving tactical skill? Do they need to study the classics? Should they concentrate on endgames? Would it help to play blindfold? There are innumerable book...