因为黑山能被释放自 塞尔维亚 in 1444 it is a good strategy to start as them and destroy the Serbian economy and manpower by disbanding the troops. Go into banktruptcy as Serbia and release Montenegro and play as subject. You should also insult or otherwise damage relations with Bosnia and other Balkan minors so the AI can't ally them. Immediately truce break and take as much land as possible. After Serbia is defeated you can move to 波斯尼亚. You probably wont have manpower after the war with Serbia, so merc up and go into loans. The biggest obstacle is time because the longer you wait the more powerful the Ottomans become, so you don't have time to wait for manpower to recover.
First idea group should be diplomatic as the only friends you will be able to find otherwise are Italian minors which won't help you much in your wars and will likely call you into their wars. After you have taken out Serbia and Bosnia try to attack 威尼斯 for Dalmatia if they are at war with the Ottomans. After you take Dalmatia you can focus on conquering Italian minors. By this time they should have already left the HRE, but if not then they will probably leave soon . Alternatively, after taking Dalmatia - as your total development will be rather low - if you improve relations with the Emperor of the HRE(usually 奥地利 so you can start improving relations with them as soon as possible) you may be able to join the empire itself for some added protection vs the 奥斯曼.