Retain perspective: How important is that, really?
You can control only your effort, not the outcome. Do your best and then let it go. How your work is received or what others do with your work is usually beyond your control. If there's nothing you can do about it, simply move on to the next task. If worse comes to worst and, for example, you get fired, it usually means there's something better waiting for you. At least think that way. It'll reduce your stress.
Avoid rushing. What causes stress is not so much working long, it's the fight-or-flight response that comes when you rush. If possible, start early, stay late if necessary, but avoid rushing.
Be nice. If you look for maximum opportunities to be nice to people, you'll feel less stressed and, in turn, people will likely be nicer to you, which will reduce your stress further.