Thou shalt use accuracy.
Thou shalt practice transparency.
Thou shalt not plagiarize or fabricate.
I believe these three journalism "commandments" should be followed by all who seek becoming a professional in the journalism field. They will not only keep you out of jail, but they will also allow you opportunity to become a more credible source of information in the public eye.
Accuracy is the first point to ponder. If a story is not accurate, how can the readers trust the information from that source? Double checking names, dates, locations, quotes, facts, sources to contact, etc. MORE THAN ONCE is a necessity for any article. Besides grammatics, it is important to analyze the truth represented through a story. Do quotes portray what the speaker actually meant? Do photos misrepresent an event in any way? These are a few questions to ask.
Transparency is another important factor dealing with gaining and maintaining public trust. I think we see this in bloggers who have captured the attention of the public eye as credible, honest, and open to criticism. They just put out their opinions and the facts that they've found to be true, not holding back information they believe to be true, and in turn they gain public trust.
My media law teacher continues to remind us of this rule, despite the fact that we had our test on libel a couple weeks ago: Do not plagiarize or fabricate! It's self explanatory really. Using actual quotes you've heard with your own ears, writing stories based off of interviews YOU conducted as a journalist, and giving credit to any additional sources are just a few keys to sticking to this rule. "So stay out of jail and abide by these commandments," thus saith your future editors!