Do's
Pump tank every 4 years. It's a rule of thumb that can be applied to any homeowner that's not sure how often to pump the tank. Some companies like you to do it more, which might be right. Four Years is long enough to ignore the tank. Things like mesquite tree roots and vegatation WILL cause damage if it goes unchecked longer than that.
Space out water use at home. Put timers on showers.
Divert Grey-water to a tree or plants. Understand that washing machines are water hogs. They use a ton of water, then it usually finds it's way to the tank. The water is too clean and slows the breakdown process inside the tank. Manufactured homes are easy custom projects that can be DIY.
Install risers if you can...no more digging costs.
Dont's
Don't Park anything bigger than a Harley on the tank.
No paper towels
Don't dump Copper Sulfate into tank (goes in D-Box)
Don't think the problem is gone by a flush. That's an expensive way to think.