Have the tank pumped to prevent the buildup of excessive sludge in the tank. This will prevent any sludge from getting into your septic field and plugging it up. This is a requirement in some communities.
Adding a "starter" such as Roebec (sp) after the tank is pumped doesn't hurt, but isn't necessary.
Some people try to limit using the garbage disposal, clotheswasher discharge, etc. My 30+ years of personal experience with septic tanks indicates this is a minimal concern.
Repeating, the most important thing is to have the tank pumped every 2 years.
Good Luck!
Dodgeman