Some factions have a harder time than others when it comes to diplomacy. The French for example get ganged up on simply due to their location. At least in my two campaigns they did. The English dont have it too bad nor does Denmark. I've played Spain a couple times now and they manage to keep peaceful with most countries. If you play a faction like HRE or France where you are surrounded by other factions you are more likely to get ganged up on by other factions. Especially once they realize you are becoming a powerhouse. Might want to try a faction that has their back to a corner with only rebel territories behind them or the sea.

If the thought of changing the time scale to 0.5 has you worried try 1.0(1 turn=1year). I'm using it and I enjoy it alot. Allows me to take my time in the game. I dont have to rush out and conquer the world. I can take my time and develope as I expand.