Need Help On Query Optimization

Hi all,
I have the following query to be optimized. It just takes too long to complete the execution.

----------------------------------------------------------------------------------
SELECT COUNT(*)
FROM Tbl_A a
INNER JOIN Tbl_B b
ON a.AID = b.AID
INNER JOIN Tbl_C c
ON a.AID = c.AID
INNER JOIN Tbl_D d
ON d.DID = a.DID
INNER JOIN Tbl_E e
ON e.DID = d.DID
INNER JOIN Tbl_F f
ON e.EID = f.EID
WHERE a.Col_1 = 1
AND (a.Col_2 LIKE N'%abc%')
AND a.Col_3 <>
CASE
WHEN d.Col_1 ='ABC' THEN 'BR'
ELSE ''
END
AND c.Col_1 =
CASE
WHEN d.Col_1 ='ABC' THEN 'ABC_COMPANY'
ELSE 'PPRO'
END
AND f.Col_1 = 'val1'
------------------------------------------------------------------------------------------------------------------

here is the estimated records for the tables.
------------------------------------------------------------------------------------------------------------------
Tbl_A has over 150,000 records
Tbl_B has over 150,000 records
Tbl_C has over 450,000 records
Tbl_D has over 33 records
Tbl_E has over 4000 records
Tbl_F has over 5000 records
------------------------------------------------------------------------------------------------------------------


Thanks in advance,
Soe Moe