My way of fighting Angelo Credo:
1. When he throws a lance at super fast speed, use Snatch to knock it down to gain some Green Orbs to recover your health, or time it with your Buster to throw it back to Angelo Credo. This damages him a lot, and leaves him defenseless for a moment.
2. When he does the three hit combo, with a finisher of him smashing his sword to the ground, go to the right side of him, use this combo:
Streak -> High Roller -> Buster
This combo can deals nice damage to Angelo Credo.
You can use your own combo, but I prefer the combo that I listed above.
3. Most of his moves can be dodged by precise Side Roll or Air Hike. Use each move according to the situation.
4. Angelo Credo can block any frontal attacks due to his shield. To have a chance of using the Devil Buster on him, use Buster multiple times when he is vulnerable to make his shield becomes weaker (red glow shows that the shield is getting weaker). When the shield stops glowing, that is the chance for you to use a powerful Buster, Devil Buster, or any other Red Queen combos while in D.T. Mode.
5. When he lost a lot of his health, he started to summon swords like Vergil's Summoned Swords. He can use it for offense and defense. You can dodge it easily, but when the swords surrounded you, use D.T. to destroy the surrounding swords to gain more Stylish points and to avoid damage, or just use Air Hike to dodge it.
6. Angelo Credo will be much more aggressive and moves faster when he is in low health. It is best to finish him as quickly as possible.
7. Do NOT use Snatch on Angelo Credo when he is walking. Angelo Credo will rush towards you and ram you with his shield. However, you can use it to your advantage as he is vulnerable at the back after using the ramming attack.
8. Blue Rose normal shots are not really effective in this battle. You can use Charge Shot 3 to deal some damage on him. Use it whenever he is not attacking.
9. EX attacks can deal good damage on Angelo Credo, but a risk must be considered as Angelo Credo's shield can block ANY Nero's EX Attacks.
Hope this helps.