Combat Basics
The most important part of "God of War" is combat. No matter how well you build up your character, if you don't know what to do in combat you will have trouble progressing. The key to doing well in combat is tailoring your strategy to the type of monster you are fighting. Small, weaker monsters can usually be killed effectively with quick attacks using the square button with the standard Blades of Chaos (Blades of Athena in "God of War II"). Grabbing with the "O" button also tends to be very effective against weaker enemies. Against larger enemies like minotaurs and cyclopes, try to keep your distance and use the square, square, triangle combo to cause damage while staying as far away from the monster as possible. Basically you want to use the length of the Blades of Chaos to score hits while keeping enough distance between you and the monster that its attacks will not reach you; you should retreat when necessary to create more space. Usually it is best to keep your distance in this manner against large monsters unless an "O" symbol appears above their heads, which indicates that you can rush in and activate a grab sequence by pressing the "O" button. Always activate "O" button sequences when you can, since they tend to deal a considerable amount of damage and often result in instant kills. Magic abilities should be reserved for difficult battles against bosses or large rooms full of strong enemies.
Bosses
Bosses are epic encounters against huge monsters or other heroes that are very difficult to defeat. Your goal when encountering any type of boss should be to determine its weakness and exploit it. Bosses in "God of War" almost always have devastating attacks, but once you know how to avoid them and damage the boss, the fights can become easy. Don't be afraid to try different things and die several times at the beginning as you test different strategies: You can continue an unlimited number of times in "God of War." Boss encounters are a good time to unleash your most powerful magic, as well as Rage of the Gods/Titans (hold down both of the analog sticks.). Rage of the Gods/Titans is an special power that lasts for a limited time, but while it does your attacks will be more powerful, and in "God of War" you will have unlimited magic, making it a great time to use your best spells as much as possible.
Building your Character
As Kratos fights enemies he collects red orbs that he can use to build up his different weapons and spells. In combat, doing higher combos gives bonus red orbs, so it is a good idea to use quick hits to get high combos whenever possible. The best place to spend your red orbs is on your standard blades. Every new level they attain increases damage and gives you access to several new moves. Beyond the standard blades, powering up your most powerful spells, especially ones that hit multiple enemies such as Poseidon's Rage, can be very helpful. Ignore powering up secondary weapons like the Blade of Artemis unless you have excess orbs after maxing out your standard blades and your best spells.