Integrate Sub-querying Into Queries

I should start to integrate sub-querying into my queries to make them run more efficiently and faster.Below is a query that I use often as a template, often just modifying the day, order and truenumber. how to set up a sub-query for this.

select "betatest", order, age, gender, geo, count (1), count (distinct rdz.id)
from analytics1 rdz
join analytics_2 alvds on (rdz.id = alvds.id)
left outer join analytics3 spd on (alvds.zipcode = spd.zip)
where day >= '2014-08-01'
and day <= '2014-09-30'
and order = 317228536
and truenumber = 540192016
group by "betatest",order,age, gender,geo;