what do I need to do other than what the book tells me to help my truck last and when you want to up power were is the best place to start

 

Don't crash it if you want it to last and upping power starts with more fuel! Sorry to be blunt, but starting modifications would be... fuel plate, governor spring kit, AFC tuning, exhaust. Then you might get use out of a new air filter setup, injectors and/or timing. A lot of info to really cover and I'm dead tired, so start searching!

Also, this stuff really applies best to a 12 valve Cummins. Good luck.

 

Gauges first then read this> http://dieseldatabase.com/read.php?id=58

Better than the book maintenance schedule and info here> http://dodgeram.org/tech/dsl/maint/2nd_Gen-12v.htm