You start battles with two turns. Use the first turn to plan a strategy and find cover. Staying out in the open is dangerous when facing a stronger opponent. Make sure to have the best weapons available always.
Increasing your stats is important to defeating enemies and completing the game. The five stats are Strength, Quickness, Intelligence, Willpower, Charisma and Body. Improving Body will keep you alive longer. Improve Strength and Quickness to take out enemies as quickly as possible. Intelligence powers up your special attacks.