Brute force. What I always do. It's easy, quick (unless there's a type disadvantage), and not-so-boring. (Shoot me if you disagree. I don't mind.)
I also focus on type advantages, if opponents have two Pokemon or more. For example, if the next Pokemon is a Water type, I'll switch Pokemon. But if I have no type advantages to, for example, a Dragon type, I'll just use my highest-level Pokemon and use my strongest moves to pwn them. It's always a great help.
I really hate stat-reducing moves. One, it's a waste of time for me; Two, the opponent might attack me; and three- Wait. I don't have three. But IF (Yes, a big 'IF'.) it's status-related (e.g. Poison, Burnt, Paralyze, etc etc.) I'll use it.