Play more aggressively -- beginners at Titan often underestimate the attackers advantage with a summoned Angel and don't attack when they should. On your first split (not counting the initial pre-game split), you should be setting up one of the two split legions as an attacker, which strives to maximize immediate combat power rather than longer term recruiting. Then use that guy to attack.
Even more aggressive -- use your Titan legion as the main attacker -- this is particularly effective if you roll a 6 for your first turn and get a Warlock. The goal here is to build up your Titan legion by earning Angels rather than recruiting and win the game before anyone else can recruit anything more powerful than an Angel.
When attacking you should ALWAYS offer a deal to resolve the battle without playing it out, unless its Titan vs Titan. The goal is primarily to speed up the game, but it can also be a useful way to cooperate against against a 3rd player who is winning. Figuring out what is the proper offer requires some experience, but often it is worth taking more losses than would likely have occurred in the actual battle to avoid summoning an angel when you don't particularly want to or to get rid of weak characters in a legion. When making (or evaluating) an offer for battle resolution, take note of the board situation around the battle. Leaving an enemy legion weakened in a spot where another player will get the benefit (points) of crushing it is not to your advantage.
When defending, if you're outnumbered you should generally flee (to avoid giving the attacker full points) unless you have a decent chance of inflicting crippling losses on the attacking legion. Just killing 3 or 4 weak creatures is not worth giving you opponent and angel and boost in Titan strength.