I think this is one of the hardest aspects of journalism. Remaining neutral is pretty much impossible but we have to do this to the best of our ability. It is so easy to judge and to throw our opinion into the picture because of the way we were raised. For example, I am Mormon and I have a hard time writing stories about things that are against my religion because I obviously have a strong opinion about those things. I had to write a story about gay marriage and I wanted to write things like: these people THINK they are right. If I were to have said that it makes it seem like I disagree with what they think. That would be my opinion inserted into something that should not have my opinion.
I found a cool exercise you can do to practice writing in third person so your opinion does not shine through. Click HERE to look at that. Another helpful source I found that can help people learn to separate fact and opinion is HERE. The teacher from that site is trying to teach young aspiring journalists how to affectively learn from a young age how to throw your opinion out of journalism to give people the full story.
There is a news manual online that also provides explanations on how to be a good journalist. They have a big section on the importance of placing fact away from opinion. Click HERE to read that.
Having a diverse newsroom is also part of this process. Having different types of people to cover different things can be very beneficial because different people see things differently. If everyone thinks the exact same way, the news will be so boring. If each member of the team has a different type of thinking, they can being something new and diverse to the table.