I just don't see how Montenegro is going to make it on its own (economically) given it's small population 600,000. They're going to have to increase foreign tourism.
Luxembourg, Liechtenstein, Monaco, Malta, Andorra are all pretty small and doing OK. The fundamentals of a good economy are property rights, low taxes, low trade barriers, deregulation, and freedom of movement for goods & services & labor & capital. Add in a decent infrastructure and something people want and you are there. Montenegro has huge tourist potential, but needs some work in the other areas--in the long run Montegegro will do jsut fine.