Get the facts right.
One of the popular public perceptions of journalists is that we are incompetent or simply don't care whether or not we get things right (like quotes). Oh, we got the basic gist of it, isn't that enough? No! Deadlines are rough, but don't be lazy. Every screw up reflects badly on our field. Mistakes will happen, but you can greatly decrease your odds by listening to people more closely, asking them to repeat themselves, paraphrasing events back to a source, and using a tape recorder. And here is a damage control tip if you do screw up: Call the person and apologize! Most times that's all people really want-- a little humility. Reporters and editors should be able to admit when they're wrong.
Do not accept gifts.
You should never accept gifts, big or small, from subjects, sources, law enforcement, or public officials. It is difficult enough to be fair and accurate without greed clouding our brains. On a related topic, the media should avoid corporate sponsorship/ownership for the same reason: Our business is uncovering what's really going on around us-- we will not accomplish that if we sell ourselves to the PR and advertising industries, and thereby accept the limits and conditions they impose on the truth. See Advertising and Media for more on corporate ownership.
This seems like a no-brainer, but some reporters still use deceit to obtain stories-- either by prentending to be people they're not or by printing things said off the record. Unless a story is of vital interest to the health, safety or freedom of the public, it is not permissable to use dishonesty to get it. In these special instances when we resort to "undercover" work, other avenues should have been tried first. If the reporter(s) and editor(s) then determine that it is impossible to obtain the story through legitimate means, try it one more time before you use dishonesty. The public cannot trust journalists who have earned reputations as liars, no matter how startling the truth that is revealed.
There are NOT two sides to every story.
Usually there are a hell of a lot more. Very few stories have only two sides, and thinking of your assignment in this way means you're going to miss something huge. Be flexible-- if you start digging into an assignment and what you find out contradicts the angle of your story, then change your story! And don't be afraid to stick by your guns with editors (some editors are initially unwilling to accept that things are not as they imagined).
Don't get so caught up in the trap of "getting both sides" that you seek out dissenters even when there are none. Take, for example, stories about global warming. The vast majority of evidence shows that global warming exists, yet most journalists covering this issue go out of their way to find the one, crazy scientist that insists it's untrue. They cover both sides equally-- as though both are equally prevelant and valid points of view. This is ridiculous, folks. What ever happened to common sense?
The stories we cover should reflect how the world is. Therefore, if there is an abortion rights protest of 500 people and two counter-demonstrators, it is unfair to give both points of view the same amount of coverage in that story (this also taking into account that 75% of Americans believe that abortion should be legal). Don't censor dissenting points of view, but don't focus on the fringe wackos either.
Never accept the official line.
Journalists are the public watchdogs, and as such we must question everything-- particularly people with power who have a vested interest in spinning or concealing the truth. Ask hard questions. Ask what may seem like stupid questions (assuming that you've done your research first). Above all, think critically and let logic be your guide.