As we have mentioned before your greatest helpmate in photojournalism is people. If you are anything like me it can be difficult to go and talk to people, and then take their photos. The only real way to get better at this is by simply doing it. Practice makes perfect and if you practice talking to people and photographing them you will become better at doing that when it is more difficult.
One of the best exercises for this is to get out of your comfort zone. Making sure that you walk around people, interview them for a few minutes and then snap a portrait. These things will help you to be better accustomed to doing these things in more intense situations, such as crime scenes.
The photographer that does Humans of New York is a prime example of someone who is doing a great job of this. Check out some of their work by clicking the above link.