SR FFA tips

If we're talking about default FFA, my most notable achievment is beating it with Akashi. Imagawa runs brought me nothing but pain and misery. There is probably someone here who did that though. Lately I'm having fun with DARKNESSHERO, in there I beat it as Ice without custom units and as Shangri-La with customs. Haven't tried Pencilcow runs yet.

So for tips. You're probably playing as a weak faction without good uniques (why would you need tips otherwise?). This almost always means you have only 1 starting territory, low income and strong neigbors. There are people who enjoy challenges and try to make no-neutrality pact runs, but in cases of weak countries your only chance then is to play defensively and upgrade your barrier to max level. Speaking of barriers, they are good. I don't know the formula, but even lvl 1 barrier can protect you from many attacks. Good to build them at chokepoints if you're struggling, have borders with many different enemies or don't have enough good units to fight many battles in 1 turn.

Back to what I was saying. 1 territory, weak army, strong neigbor. Okay, IIRC your starting generics have 5 or 6 in stats, so they're not that bad. Enemy uniques will crush them though. The key is your starting tactician with defeated warrior hunt. You really need a good unit to start rolling in FFA, so if you don't have it on start, you have to capture it.

For about first 10 turns enemy armies will deploy 3-4 units in battles. Formations will be wacky, sometimes they won't even have frontline. This is a great chance to shine for diviners, if you have them. Enemy numbers will be simillar to yours, so you can take chances and grab some land even from stronger enemies. But you'll be open to counterattacks, your other enemies wil try to take you starting territory and last locations will have all 6 slots deployed, so if you won't be able to take it, you just wasted a lot of time and money.

Money is a problem. You should start with a hospital or a shopping district. I prefer hospital, but you should run the numbers for yourself(for example district may be better if most your losses are on cheap-to-replace foots or you really need to buy soldiers for a good commander). If you have mikos, they're great money-savers for the beginning. If you capture monks, you can recruit them, then sell all their units on the next turn. You probably will even need to use flags on "heal 25 troops on every unit" actions.

You probably won't have enough units to scout until you recruit some prisoners, but you probably won't need it. AI always tries to send uninjured units (except when he defends his last province), so dealing enough damage to his important uniques may make sure you won't see them for some time. AI has trouble healing troops, so prolonged wars will weaken it greatly. As will capturing and killing commanders.

About captures. Strong unimportant uniques are easily noticable and great targets for capturing. They won't die while on AI's side and can only be captured. Important uniques of course cannot be captured until they become ronins. But mostly you'll be capturing generics. You really watch closely to damage in battles to see if someones stats are good. You can easily see the difference between attacking a 3 DEF unit and a 7 DEF unit. Same with ATK. Now, for the types.

Warriors - get units with at least 6 ATK. High SPD is great, DEF is preferable, but you can make use of glass cannon warriors too.
Foot Soldiers - don't release them, foots die more often than any other type because they are in most danger of being annihilated. In midgame you should have at least 4 foots with at least 5 DEF because you'll need to protect backline. Not always though. When fighting really strong opposition, where you fear you foot WILL get annihilated, it may be better to sacrifice worse foots. That's when these 1k 3 DEF stacks may come in handy.
Archers - garbage. I struggle to use even 8 ATK archers, volley is bad, foot soldier snipe is usable, but situational. No, really, sometimes FSS is the only thing to deal good damage to guarding foots.
Ninjas - good enough ranged units. They're fast, so can cripple strong enemy units before their turn, may have more turns than other units, giving more turns to your side and giving less to the enemy and can break preparations. This is the main reason to have them in reserve. And assassinate is good, but don't count on it. On the downside their damage is pretty bad. I probably won't take ninjas with less than 7 ATK.
Monks - skills are situational. If they have good stats (mostly ATK) then take them, otherwise warriors are better.
Mikos - good in early game and defensive battles, will alleviate your money problems. At least 6 INT. All of the above miko discussion applies.
Tacticians - really good. I'd even take 5 INT tacticians. I haven't seen generics with Battle Rating Down, but we all know how buffs change the flow of battle. If you're playing DHR, where you can upgrade them, then all the better.
Tebasaki - godsend. You can compare them to warriors with 2 ATK higher then theirs. And this is without taking in account better speed, ability to attack backrow and chance to have Battle Rating Up. Even 3 ATK tebasakis can be used, you'll probably get better ones.
Musket - wouldn't advise. Having unit with only 1 action is bad, most of your damage often comes from the frontline and warrior should outdamage musket user in 2 attacks. If you really need someone bursted down then you could. I mostly just don't like them. Except Special Cannon.
Diviner - amazing in early game, where they'll fire of all their shikigamis. Later they'll be used only for guard shikigamis.
Mage - generic mages exist only in DHR, don't they? Can be used against foots because of their magical attack. Damage is fine. INT 5 will probably be enough.
Peasants - once upon a time I captured a peasant with 8 in all stats. I didn't recruit him.

Don't forget to look at non-combat stats. You should have some units with good Search on scout duty. Negotiation and Construction will help too. If after selling it's troops it will have 0 cost - even better.

The breaking point is getting 10 territories after which you'll be able to upgrade buildings. You see, mansions are strictly better than other buildings money-wise, you just don't get the value from them, while struggling in the beginning. But AI's troops are always increasing, so you'll need mansions to keep up. So it's finding the balance between present value of healing troops and recruiting troops to good units and future value of having many large usable troops.