Need a refresher on basic NiMH usage and care

I managed to snag a 7 cell 4200mah Trinity reference nimh hump pack for cheap online for my friends Stampede. He's been running locally purchased 6 cell nimh packs but I don't think he's been taking proper care of them as they don't last as long as they used and don't have same power output as before. I want to prevent him from ruining this nice nimh I got him.

Could someone lend me some links that I could print out basic nimh usage and care for him to follow? He's using a Dynamite Prophet plus charger.