What’s the best way to manipulate enemies?

What’s the best way to manipulate enemies?
Coercion. Tricking them into doing what you want, by making them think you're doing what they want. Plans within plans within plans. Don't give any clue to how much effort you've given to dealing with them. Trick them into underestimating you. Plan it like a multi-stage ambush. Come at them from several perspectives, and while they scramble, launch the second volley from just as many different directions. Leave them scrambling to cover for themselves.

Learn your enemy well enough that you could pass as your enemy, and then as your enemy, answer your own question.
How do they think? That is how to manipulate someone. That is how you puppeteer an election to help your friend win.