I had similar problems with blow outs. I changed from my Goodyear Marathons to Maxxis and changed my driving / loading habits and have had good luck since.
The following are my tips:
#1: Hit the scales. Ensure you aren't overloading the tires
#2: Watch your speed. I used to drive at 70+ mph. I have now slowed it down to 60 mph or lower.
#3: Tire maintenance. Cover them from the sun when you store for any length of time. Keep up your tire pressure (cold inflation) and check it often.
#4: Purchase a TPMS. They watch your tire pressures and temps while driving. Good piece of mind.
#5: Have the tires balanced.
#6: Watch the heat. Any blowout I've ever had happened when the weather was 95+ deg with strong sun.
If you have the rooms to do so, upgrading your tires (and possibly rims) will be an added benefit. Even when doing so, the tips above are good practice.
Good Luck!