Tip when playing with Plus (can be handy for general play too when you're outmatched card-wise):
Drop a card in the center of the board in your first turn, the AI doesn't seem to coordinate Same/Plus very well but simply having a card there gives you many more opportunities from the start.
For non-plus games it can still be handy when you're using a weaker deck VS a stronger one because depending on how the NPC behaves you can strategically choose when to win that card back (because it's in the center you'll have ample opportunity).
The AI plays very defensively and will often not even flip the center card immediately because it likes to stick to the corners, so if anything you can get them to start dropping their cards without flipping any of yours.
Beyond that, it's just a good way to alter your strategy and get you thinking in different ways, can give you a better idea of how the NPC behaviors work.
XI Wiki



