how would you speed up this long query?

select
sub_query_1.pid,
sub_query_1.tit,
sub_query_1.num,
sub_query_3.cid,
sub_query_3.id,
sub_query_3.c,
sub_query_3.s,
sub_query_3.z,
sub_query_3.cy,
sub_query_3.cd,
sub_query_3.cr,
org.id as org__id,
org.pid as org__pid,
org.open,
org.cid as org__cid,
z0.zcg
from
(select
proj.pid,
proj.tit,
proj.num
from
proj,
(select
org.pid
from
org
where
org.open = 'Y') as sub_1
where
proj.pid = sub_1.pid) as sub_query_1,
(select
detail.cid,
detail.id,
detail.c,
detail.s,
detail.z,
detail.cy,
detail.cd,
detail.cr
from
detail,
(select
org.id
from
org
where
org.open = 'Y') as sub_3
where
detail.id = sub_3.id) as sub_query_3,
org,
z0
where
sub_query_1.pid = org.pid and
sub_query_3.id = org.id and
sub_query_3.z = z0.zcg
group by
z0.zcg,
sub_query_1.pid,
sub_query_1.tit,
sub_query_1.num,
sub_query_3.cid,
sub_query_3.id,
sub_query_3.c,
sub_query_3.s,
sub_query_3.z,
sub_query_3.cy,
sub_query_3.cd,
sub_query_3.cr,
org.id,
org.pid,
org.open,
org.cid