First, always bully weaker but historically friendly countries. They pretend friendship in order to take advantage of you. Make sure they only receive services from you–market access, resources, and security–at the market price. If they don’t like it, who cares? They have nowhere else to go.
Second, suck up to dictators with nuclear weapons. Unfortunately, you have little leverage over them except the threat of overwhelming force, which is too dangerous to use. Your only hope of influencing them is to openly admire them, so make a display of treating them as equals and colleagues and see what happens.