(Well I may be stepping on my soap box but here goes...)
1. It took me three years to realize that I need to stop comparing greener grass. In my experience, everyone from DMA 210 to the $2,000/day rate freelancers complain about how horrible things are. There are valid things to be upset about, but an upbeat mindset in the worst of situations will provide better mental health. The last place I was really unhappy working at, started getting a lot better when I repeated to myself "When the station you work for is a joke, make sure to laugh."
2. Respect your mental health, and be able to turn off every now and then. Find a hobby that has nothing to do with TV. I learned to sew a couple years ago, I'm not good at it, but I've made a couple sand bags, cell phone holder and some other odds and ends. Stepping away from ENG will help you last longer in ENG.
3. Keep a journal or scrap book. (Like mentioned above.) I'm not prefect at keeping a journal. One year I starting writing down every VOSOT, live shot and package I worked on in a day by day calendar. I was amazed by how much I did in just a couple months. I have also saved every press pass that I can. I started hanging them on my closet door handle, I have so many now I have to hang them on two handles.
4. Be humble, but don't belittle what you do. I saw every presidential candidate last year. I met a guy who will probably change spinal cord injury treatments in the next 10 years. I've done a 180 in an air boat, flown upside down, and road along w/ cops as they hunt down fugitives. We have a really cool job, it is OK to let friends and family be envious of the amazing things we get to do. Just don't rub it in & become obnoxious.
5. Befriend as many people as you can that you can trust for good advice and critiques. Finding people who can tear apart your best package frame by frame, without making a comment about you as a person, are a real blessing. You have to be humble enough to realize that critiques are necessary and wise enough to recognize the people who critique to help and those who critique because they had a bad day.
6. Lastly and most importantly, be professional, but also be human. It is our job to swarm to the worst of humanity and take pictures of it. Recognize that this is your job. Putting pictures on TV of a crime scene or someone in court will be very hurtful to people connected to the story. You MUST remain objective while on the clock, but don't become so thick skinned that you lose touch with the world. Every time I have shoot something awful, I make sure to turn my feelings back on when I get off my shift and process the emotions of darkness.