Master Steeds said:
so everyone, what are/were you/your tactics for playing the game?
1.
Spam Ninjas and Monks. You can win the game without declaring war on anyone. Have your Ninjas sabotage any and all Rice farms they can find and to keep them sabotaged, as well as any markets or temples, or anything that gives happiness or money. Repairing heavily damaged buildings costs a lot of money and you'll soon bankrupt the target clan. Then their public order will start to drop due to starvation and uprisings will start. Meanwhile, your Monks should go around demoralizing armies and converting agents to train themselves up. Once they get the +4 to Inciting Unrest skill, just send them to a province with negative public order and have them start a riot. I've wiped out entire major clans without attacking them once, just mopping up the rebels and minor clans that take over their provinces.
2. Early on, your best bet is to attack when they aren't looking. The AI will often leave their cities poorly defended and you can sweep in and lay down the pain beofore they can react. In my Usuegi campaign, I jumped on Takeda while their whole army was south, took 2 of their 3 provinces and forced them to become my vassals, without ever facing their army. All those Ninjas you've been building can help here by sabotaging armies in the field and giving you free reign.
3. Try to fight defensive battles if you can. If you're fighting a war, it's only a matter of time before the AI attacks you. If you can predict where the attack will come, you can station a sizeable force in that town and defend from the castle. If two armies of equal strenght fight over a castle, the defender has a vast advantage and can wipe the floor with the attacker while suffering only minimal casualties. Then, when the enemy's main armies are dead and broken, just swoop in on his poorly defended castles.
4. Don't spam Samurai early on. It's tempting to start training Samurai from Turn 1, but it'll ruin your economy. Stick with Ashigaru units at start and then gradually start adding in Samurai as you expand and get a higher income. Eventually you want an all-Samurai/Monk/Hero army (unless you're Oda), but no need to rush it.
5.
GET THE TRADE NODES! On Turn 1, upgrade your port. As soon as it can build Bow Kobayas, start building them and sending one to each and every trade node on the map. If you get to one and there's nobody there, park your Kobaya on it. If someone is there, park your Kobaya nearby and wait in case they move or are chased away. Then get Trade Ships and get that sweet sweet trade income rolling. Just remember to mix in some Kobayas and Bunes with your Trade ships, those Pirates can be nasty.
6. Beware the Realm Divide. It's the downright atrocious hit to your diplomacy that occurs when you capture Kyoto or get to 16 provinces. Pretty much everyone except your closest allies will declare war on you. If you find this mechanic to be annoying and/or unfair, look up a mod for it that changes or removes it.
7. Either have more Cavalry than the enemy, or don't have any at all. Cavalry is only good if it can operate freely and it can only do that once it whoops the enemy cavalry's arse. When playing as Takeda (better cavalry units) my 5 Katana Cavalry would quickly establish dominance over the enemy's excuse for cavalry and proceed to harass, flank and destroy the opposing infantry and archers. Even Spearmen aren't much of a threat if charged from behind. In siege defences, deploy your cavalry outside the walls and have them hunt Archers. The AI will sometimes deploy isolated groups of archers that are easy to mop up.
8.
NEVER BREAK ALLIANCES! The diplomacy hit you take is awful. Also, don't ally with clans who might declare war on each other, because then you'll have to pick a side and betray the other guy. It's best to pick one strong clan which doesn't hold any of your Victory locations, ally with them, and then ally with their allies/vassals. That way you can be fairly sure your allies won't go homicidal on each other.
Hope this helps. If you have any more specific questions, I'll gladly help.