There are remarkable similarities between the independence referendums in Catalonia and Iraqi Kurdistan. And those don't bode very well for their success.
In both cases the local governments acted out of a kind of despair. The Catalan case is the most obvious. Its government had lived above its means. So it would soon need to apply budget cuts. And usually translates in losses at the ballot box. And given its thin majority in parliament that would be the end of Puigdemont's rule. In Kurdistan the oil price crash was still hurting. And soon the Iraqi army would be free to confront the Kurds.
In their hurry - and arrogance - both made also the same mistake of antagonizing the other ethnic groups. The Kurds have gotten a rather bad reputation for sidelining other ethnic groups. Puigdemont's disregard for parliamentary rules and the fake history that he has gotten taught in Catalan schools are lighter problems but point in the same direction. In both cases the way people try to achieve independence suggests that life will get tough for other ethnic groups if they win.
The best strategy to get independence isn't rocket science: Make your effort when your economy is flourishing and the prospects are still good. That position will allow you to be generous to the country you want to leave. Be nice to other ethnic groups: you don't want to antagonize them. If you play it smart you can even get their support: they too will profit when your rich province becomes independent. And most important: be patient. There are lots of small steps that you can take until one day the stars are aligned in the right way for your big move.
Maybe one day the Catalans and the Kurds will have independence. But we can only be glad that the rather nasty characters of Puigdemont and Barzani didn't succeed. They would very likely do a lot of harm before the situation stabilized. The independence process of Slovenia and Croatia offered frightening examples of what happens when you give in to nasty politicians who want to steal independence.