For long term results, always ensure too that your priests get a place in the College of Cardinals, have a priest always posted in every settlement, getting them out once in a while to boost their piety. Having your priest elected as Pope is highly beneficial for like 30 turns as it enables you to call any crusade at your whim. As for military concerns, hire an assassin to take out their pesky generals and to sabotage their towns. If you are short on money, be on the move in capturing other settlements to distribute the upkeep cost of your armies