Bowling spinners in limited overs games is a big mistake. The CPU finds it very easy to hit you for six often.
Try to fill your lineup with fast bowlers or medium fast bowlers and avoid spinner.
Pitch the bowl slightly outside the off stump, just towards the crease line. Then, start with in swinger and when it is ready to pitch, change it to out swinger. It will get you a lot of wickets in the slip regions and backward point region.
Other delivery to baffle the batsman by starting with Off Cutter and Bowl Leg Cutter at the last minute.
Set the field where you have fielder in closing catching position and bowl according to the field set. Remember the outside the off stump and out swinger is your delivery