How do I parallelise a simple SELECT query?

Try this:

select /*+ PARALLEL(4) */ * from employees where dob < to_date('10/10/1985', 'DD/MM/YYYY');

See more from Oracle Hint.

See also this answer to see why PARALLEL did not applied on your SQL statement.

sql oracle parallel-processing

/*+parallel(8)*/

has decreased by search time from 16secs to 3 secs. So, I could definitely say it works :)

CodeHunter