Unlike level bombing where you complete a procedure to get accurate bombing, dive bombing is more feel and practice related.
You will always get the training sights in the TA for them, try a few practice runs bombing and rocketing stuff. Steeper dives give better results but with practice you can do rocket attacks at shallower angles. Try to use similar dive angles and notice where the training sight is on the attack. Then try an attack, maybe off line or in MA without the training sight, and see how you do. In steep dives from altitude compression and remaining in control of your aircraft is also a factor.
Also, try NOT to use any rudder input on your attacks.