Tip: Going to war as a small nation, a checklist.

Anyone can win wars easily when you are the giant blob who can siege down kingdoms with just their retinue troops, but going to war as a smaller nation requires more care and planning. Here is a checklist of factors to consiter before declaring.

1. How many troops do I have, and are they maxed out? (Generally good to wait for your levies to recover. Using the train troops mission can further help)
2. Do I have any factions who are sitting at 20% or higher? (Going to war and losing troops will increase faction % of liege ratios, making them more likely to fire mid-war
3. What is the status of my target's military? (Nations that are at war with someone else are generally good targets... especially if that war has been dragging on for years. Check the warscore)
4. What is the status of my target's allies. (Especially important for holy wars, if your target is weak but ALL the nations it is friends with are strong, you may find yourself overwealmed)
5. What is the status of my threats. (Nations who have claims on your stuff are always a threat...even if they don't care about your initial target. If a neighbor with a claim has been at peace for years, get ready to fight on two fronts or don't go to war until they are distracted)
6. How much money do I have? (Always have enough to hire an additional merc band, even if your initial attack includes mercs.)
7. How much money does my target have? (Very important when attacking republics)
8. Can I weaken my target first before going to war? (Sowing dissent is OK...but murdering a leader with a child heir is better. If you can throw a nation into chaos first, going to war becomes easier.
9. If my ruler dies during the war, will I still be able to win it? (Unless it will be a quick war, be wary of starting long slogs when your ruler is older or has -health traits. If you have a well-liked heir, this is not as much of a problem).
10. Will I be able to make use of, and defend my new land if I win? (Snagging a county with a weak claim when they are rebelling is great... grabbing one halfway across europe...not so great.)

Having started as a count in Navarra...these tips have served me very well in establishing a very strong presence in Spain very early in the game.