You can get actual big five tests online (see the latest LW survey for an example). The big 5 tend to be pretty stable, but putting your self in a social group that has the trait you want is relatively effective. Also, there is a whole lot of YMMV on which one(s) to use, but organizational/productivity tools like Getting Things Done can allow you to act in usefully conscientious ways without changing your personality per se.

Yeah, me too. I found getting a relatively structured job with standards so low that my (minimal) natural levels of professionalism exceeded their requirements successful. Conscientiousness is really, really difficult to train, but you can move further from your current base by changing the people you hang out with or work with. Industriousness, OTOH, is trainable. Last comment I saw about this, good paper linked.

You can do better but having low conscientiousness still blows.