Characters, combinations, and AI
Every character has a different set of skill, and therefore is meant to serve a different purpose. Reyn , with his high HP and tendency to draw aggro, is the perfect tank. While he’s absorbing the attacks and attention of enemies, Shulk can move behind to pull of backslashes.
AI and the break, topple, and daze combo
Characters like Dunban have the ability to break, topple, and daze all by themselves; however, AI-controlled characters are far more likely to follow up a break with a topple than they are to initiate the process with a break of their own. As such, it’s a good idea to break on your own and hope your AI pal will follow up with a topple move.
A good example is the pairing of Shulk and Reyn. Shulk has more than one way to break an opponent, but no easy way to topple. If you use Shulk to initiate break, Reyn should automatically use a topple move (if it’s available). Because you then have a very small window of opportunity to daze, you should use Shulk for that purpose.
Always make sure you have your party’s arts configured so that daze is attainable. Even if the enemy you are fighting is resistant to break, chances are you can break through that defense by trying the moves during a chain attack.
AI and ether use
Characters like Sharla and Melia base their strategies around ether arts. Unfortunately, Xenoblade’s AI has trouble effectively utilizing these abilities during crucial moments, so you may want to try taking direct control of these characters during important battles.
For instance, Sharla has a number of highly effective medic skills, making her one of the best characters in the game. But the AI doesn’t seem to understand when to use certain skills, such as the party-curing Heal Round, if at all. The same concept applies with Melia’s summon spells. Perhaps you prefer to summon a flame first to bolster your party’s strength, then follow up with two summon bolts to use for offensive purposes. The AI doesn’t recognize when strategies like this are needed, making Melia almost useless unless you’re directly controlling her.
Some NPCs, whether they give quests or not, only come out during certain times. A good strategy when scouring a town gathering quests is to do a second run after you’ve fast-forwarded the clock 12 hours. This ensures you will have access to virtually all of the NPCs currently available in a given area.
The same rule applies to monsters and unique monsters. Monsters are generally stronger at night, and if you’re hunting for a unique in a certain area but can’t find them, chances are they aren’t ‘awake.’ Fast forward the clock and see if they appear.