- sanction the leaders responsible and their buddies, the most common (that's what we do with russia, turkey, ...), hurt their wallet but ultimately is a soft sanction, and also your populace sees it as ineffective / nothing is done
- sanction the country directly, embargo, complete block, kick out of swift, that sort of stuff is what was done to Iran. Can only be done if you're part of the bigger/more powerful group. Massive effect, causes lots of poverty and pain for the populace but that's on purpose, so they are forcing their leaders to change some stuff. Doesn't always work, but both outcome are victories in a way: either the country is forced to change and stop the original abuse, or it doesn't change but is so crippled that it's not longer a problem.
This is bound to something very, very, important: if the country does change and does what you asked, you start lifting.
Part of the message that's more of an european rant: that's why Trump action on the Iran deal was a disaster, because, now the population doesn't believe it's their own leaders fault, and even if they did their leaders don't believe it would ease if they did what was asked. That's how you end up with a north korea.
According to every report I've seen, Iran was fully respecting their part of the deal, and allowing all the inspection necessary, when the USA did a "AHAH ! it's a trap !" trick on them and screwed them. You're not convincing countries to behave, you're telling them that if they don't behave, they better go all the way to the other side.