The Basics (Foresight)
Now, to wage a successful war, you must take a look at many aspects of your countrie's political demographics. It is portrayed in the game that conservative political veiws tend to be more diplomatically agressive during this time period. Also, it is important to look at your opponents political demographics and diplomatic history, as it may give valuable clues as how to approach and prevent war.
It is very important that one considers alliances, as countries with alliances will use them to their advantage. If and when you attack another country, allies on all sides will become immeadiatly involved, and you will find yourself with massive foreign armies marching right to your doorstep! It is very necessary to take into account how alliances may aid or hinder you.
When another country asks for an alliance one must consider the offer, even though it may be tempting to just acept the offer. The smaller countrys might be offering an alliance because they are going to need help and larger countrys may offer an alliance because they are trying to gain leverage over you. Kinda like I scratch your back you scratch mine. An alliance with a small country may mean a war with a big one! Always check the countries previous allies before chooseing to form an alliance with said country!
Be aware of the way the country is shaped. At first this may not seem like an important factor, but if their nation wraps around yours, you may be finding yourself fighting a war on two fronts. Likewise, this can also work to your advantage, if you let it. If you have allies on the other side of the nation that you are fighting, flank them. Remember, keep your options open.