Here is few things I learned over the years (they are easier said than done, but it takes practice/work).
a) start using the "off work" button. Learn that the second you step out of your job, you no longer think about it.....EVER. I've let my job get to me and my family/personal life WAY too much when I was younger. It was stupid and didn't accomplish ANYTHING (quite the opposite). When I step out the door I press the "off work" button and I don't think about it the job until the min I step back into the office.
b) don't do to little and don't do too much. I have never been to a company that appreciated and rewarded hard work, quite the opposite actually. In many companies (including my current employer) I've seen people that work the hardest get treated like crap/no reward or advance.....while people that do nothing/don't do great work etc get a raise/advance and even be considered better employees. It's fucked up/not fair and backwards....but that's the corporate world for ya. Obviously this doesn't apply to companies that got their shit together and do it right, but be careful. In the past I've seen people go UP AND BEYOND (including myself) for their companies.....and got burned doing so # of times. It's not worth it.
c) just laugh. You will see SO much fucked up shit at your job that will blow your head/make you think and wonder. DON'T EVEN THINK ABOUT ANY OF IT......Just laugh. Whatever happens....just laugh. This was by far the best advice EVER given to me in my 3 careers and 12+ places of employment. This will not only keep you sane but also add some humor to your work life.
d) do NOT dedicate your life to your job. I see people make this mistake A LOT (especially now days). Employers LOVE to force people to work unlimited hours and dedicate their life to their job. They will threaten you etc to get to their goal. DO NOT fall for that crap. Put in your 8 hours and go see your SO/Family and have a healthy lifestyle. Job is just a small part of your life that enables you to live, but it is NOT your life.
e) don't get too close to people at work/no friendships (perhaps inter office ones). More people know about you, worse off you are (when their act stops or they want to get ahead). I have a tendancy to get close to people/relate etc and it has ALWAYS ended up hurting me in the end....when people show their true color (it can take weeks/months or even YEARS). Just come in, do your work, be friendly and get on with your life.
If you don't follow these steps not only will it effect your life, it will effect your HEALTH in ways you can't even imagine.