So I just finished a game as the Confederation of North Angola, released from Portugal. It was a fun, challenging game - especially the early bits. I had an extremely small population and very little territory - just a strip of coastline. I was, thankfully, civilized and inherited Portugal's tech, but it was still quite challenging in the beginning. I spammed culture, commerce, and industry techs so that I was rank 16 by the time the Scramble occured and managed to carve out a large slice of Africa - and conquered Mozambique.
What really helped was conquering Transvaal before the Scramble occurred. Their gold provinces were life savers in actually funding things; I only fought four wars of aggression this game. Transvaal, Oranje, and two against Mozambique. Oranje was the only challenging one; I had to fight both the USA and the UK since they were in the UK's sphere and friendly with the US, but I managed to cause the war to be so costly for the US (the war leader) that they eventually white peaced out.
I didn't really accomplish much of note, but it was a fun, isolationist game and I eventually adopted business schools & tycoon capitalism, focusing largely on just letting my country run itself, and it did OK, I think. After I hit secondary power status I don't believe I fell out of it once, but I never managed to climb to great power status, either, though I didn't try very hard.