Honestly!
If you are doing public relations you have to be honest. Your good reputation is largely going to determine the reputation of your company. Any lies, any cover ups, even any omissions of the truth will come back to haunt you. If you tend to be a bit of a liar you might fare better in creative writing than in public relations because when you are doing public relations, everything you say, write, or do is going to be scrutinized. Even one slip up can soil your reputation forever in those circles.
Fortunately, it is easy for most people to be honest. Make sure you only make statements when you are sure that what you are stating has been double checked for authenticity. Even if you are totally honest, if you are not careful about checking your facts you might release information that makes others question your integrity. In public relations, this can be a disaster.

