Optimizing a read-only database

Dear List,

I would like to know if somebody is aware of tricks for optimizing
PostgreSQL settings for a read-only database.
I have a big read-only database (> 1.10^9 records splitted into ~ 10
tables) using GiST and Btree indexes, no foreign keys on tables at all.

I believe that not doing locks on pages could save some time as there's
a lot of simultaneaous readers, but so far I've found nothing about this
specific case in official documentation...

Best regards