Get Your Data in Order

create table physically_ordered_data (
  can_vastly_reduce_your_io   integer,
  and_reduce_buffer_cache_use integer,
  when_querying               varchar2(1) 
                              default 'Y',
  constraint on_the_leading_columns_of_the
  primary key (
    can_vastly_reduce_your_io,
    and_reduce_buffer_cache_use
  ),
  just_define_your_table_as   integer
) organization index;
IOTs are woefully under-used in Oracle. While there are some provisos, 
the benefits can be great when fetching several rows from a table via the first columns in the primary key

Martin Widlake has an excellent series on IOTs explaining how they work and their benefits and caveats. I thoroughly recommend you read it.