When you're doing intensive physical work and start to feel it build; know when to stop and step away. You might be delaying completion of your task a bit a little, but if you toss out your back or have a nerve pinch and take a fall, you're useless for a lot longer than taking a break. I pushed it on a long trip with lots of heavy baggage and equipment, and suddenly my left side started failing me and I thought I was having a stroke and I fell hard on tile. I was trying to catch a flight so I had little choice, but before that I ignored all the little pains and misused my chances to sit down and heal a little so I could sightsee. Same feeling started building a couple weeks later when I was doing some landscaping and I was still pushing it, and my leg almost gave out for a second and I nearly took a fall on concrete. So I walked away and laid down. And I felt no shame in that.

For non-physical work: take an Aleve when you feel it coming on (not too often to avoid dependence or building a tolerance) to get in front of it before it compounds.

For all the lifestyle exercise tips mentioned here, I'd add to make sure you get enough fiber. It's surprising how much intestinal distress can worsen existing back pain.