making postgres DB stable, efficient and secure

Hi,
I'm done with my database design and almost got it working (with all triggers and functions) pefectly.
Now, i need to see how can I make my DB stable, efficient and secure.

I wanted to know how should I go about it as far as postgres is concerned
What are the best practices is this regard.

Any kind of help would be higly appreciated.

Thanks,
~Jas