These Tips came from Konami's official site
1. Secondary Weapons are very, very powerful. Using these in combat will pay huge dividends and make the game much easier. Each secondary weapon is strong or weak against certain enemies. Read you bestiary and check what enemy is susceptible to what secondary weapon. Find the right combination and a secondary weapon can give you a one hit kill.
2. Use Holy Water on undead enemies such as Vampires or Ghouls.
3. Use Daggers on Lycans.
4. Combine magic with your secondary weapons for devastating effects. Light Magic combined with Holy Water creates divine shield around the player granting temporary invulnerability.
5. Shadow magic with daggers will cause major damage to Greater Lycanthropes and any Werewolf type enemies.
6. Light magic combined with Fairies will devastate Sword Masters and Vampires, turning your fairies into powerful suicide bombs.
7. Use Dark Crystals on Bosses. It damages them greatly or use to clear an area without engaging in any combat.
8. Check your bestiary often. Important information is there for you to maximize your strategies.
9. If you are finding an enemy difficult to defeat, you might be using the wrong tactics. Some enemies are strong against certain items and magic. Check the bestiary.
10. Master sync block even bosses and Titans are susceptible and in the case of bosses can leave them open to counter attacks.
11. Dodge often and counter attack.
12. Never use the same attack over and over as some enemies will get wise to you and change tactics.
13. Stomp seems very weak but is actually very powerful against enemies who can attack you whilst airborne. using stomp means you can attack i the air out of reach, stomp and continue attacking on the ground and then in the air again.
14. Focus is the only way to keep the magic flowing. Stay focused and use the orbs to keep your magic in tip top condition.
15. If you are losing a fight over and over...go find some upgrades by revisiting previous areas and make yourself stronger then come back.
16. A good tactic is to stock up on secondary weapons before a boss fight. Break objects to get your stocks up.