I still find myself getting destroyed in most fights as I don’t understand what I should be doing in combat. My main strategy, if I can even call it that, usually is to hit them and hope I can down them before I lose. The farthest I’ve made it is the Mossy Expanse vi getting fucked senseless by every npc. The few times I’ve fought the Dark Knight my lack of knowledge always ends up with me getting railed and game over’d.

I’m not sure which perks/skills are useful to me, nor am I sure which class would be best to start out with. I know this is a broad question, but any advice is welcome.

if you want a hiro good at combat, which is a good starting point, warrior is the best start hands down. Once you know the system, you can perform with a character built less specifically for combat, but having raw stats to fall back on makes the learning much easier.

strength increases your damage with most weapons, and makes enemies lose more balance/stamina as you hit them

endurance is probably tied for most important stat for a fighter that can't oneshot everything. It affects your stamina, what armor you can use, and directly subtracts from how much damage you take.

agility it the other stat most important for a fighter. It increases damage with most weapons, keeps you balanced (losing balance is basically an insta lose because it forces you to go prone), it lets you dodge attacks, it lets you land attacks more often. It's the god stat for moment to moment combat.

perception lets you see what nodes are coming up in the overworld, but more importantly if it's high enough it lets you read what your opponent is going to do on their next turn. Unless you're horrendously overpowered this is very good.

magic does little unless you choose to be a dedicated caster, which is a whole other system that largely ignores stances and normal combat rules.

charisma is good for seduction builds and recruiting companions, but we'll just ignore those because a good fighter doesn't need to do either.

character generation: warrior with max agility and the other points into strength, perception, and/or endurance. If you have achievement points to spend, extra stats is excellent because these have a huge influence on everything in combat. For perks, faster for the extra agility is just the best one to start with. the second perk can go into increasing strength, perception, or endurance, or you can toss it to skilled to get more stances to experiment with.

skills: you always start a fight at balanced stance. The second + rank of any skill does the same as the first rank, but a little more efficiently. Getting the first rank is most important so you have your combat options, upgrading them later is just bonus that makes you a lil stronger.

from balance: low blow is a poke that isn't really meant to do damage, but does a little and can trip people if they're already faltering. your main attack is going to be spring attack to go into an offensive stance. Block is also good if your opponent is about to do a big hit, or you're low on stamina/balance.

in offensive: you're more vulnerable but are able to do damage. tempo attack is just a basic attack that keeps your stance, but staying in the same stance too long makes you predictable and your opponent will probably just start dodging all your moves after 3 turns or so.  combat guard backs you off into balanced while protecting you from an attack, while crushing blow returns you to balance AND does big damage (HUGE damage against a prone enemy) but costs a good amount of stamina. blitz attack puts you in blitz stance which is extremely aggressive. you'll do big damage but also be very vulnerable and burn through stamina hard.

in blitz: all-out blitz is basically tempo attack again, but in blitz so it hits harder and spends more stamina/balance. hold back does nothing but shifts you back into offense stance. Blitz by default is kind of a dead end where if you don't win the fight right away you're over-committed to attacking. I recommend you start the game buying 2 skills here to make it not a dead end

•  changeup is like hold back, but instead of doing nothing, you attack while stepping back into offense stance. This lets you swap stances to avoid being predictable without wasting turns.
•  Vault automatically dodges any low blows, since you're jumping, and also sets you up for falling crush on your next turn. a SUPER hard hitting move that puts you all the way back in balance stance. A great way to finish your attack and be ready to fall back to defensive if your opponent lives. Just be warned that the dark knight in particular is immune to vault. She will catch you before you land and you'll be caught between a cock and a hard place.

that's the offense down. back to defensive stance which we skipped over before. advance sucks. don't use it unless you're a caster. guard does exactly what you'd think it does. careful attack puts you back into the offense once your opponent is done wailing on your shield and you've got your stamina back. sudden advance is the same but hits harder and costs more stamina.

• second wind is a good skill to buy at the start. It lets you recover stamina very fast in defense stance, at the cost of defending yourself slightly less well than blocking. Good for after you've blocked a couple times and your opponent is running out of steam.
• if you have extra skill points, sudden attack is careful attack but stronger, at the cost of more balance and being less able to dodge

The last skill I recommend you start with is uppercut from the kneeling stance. Ideally you won't need it, but if someone trips you, you're in a really bad spot, and having a move that gets you back on your feet while also doing damage is a huge improvement over slowly standing up and wasting turns getting hit and doing nothing about it.

As a warrior, you'll start with a broadsword. You'll want to replace that with a gladius as soon as possible. it'll halve the bonus you get from your strength and agility, but add 4 damage. Unless you have more than 8 in both stats, this is a direct upgrade. and If you do have more than 8 in both stats, then you're powerful enough that it doesn't really make a difference and the gladius weighs much less 

gladius is imo the best weapon in the game. rapier is best if you only have agility, but gladius is best if strength and agil are within 2 or 3 stats of eachother which is almost always.

Mechanically, once you understand moving around in your stances and how to read the UI, it's not that complicated actually.

You spend stamina by doing most things. when low, you fight worse. If you run out, you'll fall prone and need to catch your breath. That's really bad. Endurance makes your stamina last longer

You lose your balance by doing things AND by getting hit by things. If you get low, you fight worse, and If you run out, you'll fall prone and need to stand up and regain your footing. That's really bad. Agility makes you lose less balance.

grip is a mechanic... apparently you can drop your weapon if you run out of grip? I have never seen this actually happen so just ignore grip idk.

Armor only protects certain body parts, and gets damage as it protects. While that can be very complex all it really means at a surface level is that as a fight goes on too long, you will start taking more and more damage, but tougher armor slows that down.

There are other statuses that make you better or (mostly) worse at fighting. Your opponents can have them too, but if you're focusing on combat you're better off just fighting than trying to get a werewolf drunk or making the harpy horny so it lets its guard down, so you won't be inflicting them on purpose much (apart from bleeding, which is just extra damage)

Your opponents (mostly) have all the same rules you do, and most of them have similar if not the same stances. You can see their stance, fatigue, statuses, and balance, and If your perception is high enough you can see what stance they'll use next turn. Use this to decide when to attack, when to take a breather, and when to start thinking about pulling back into defense. If you and your opponent are both in blitz/berserk stance for instance, you're going to do a lot of damage but also take a lot which might not be worth it in the long term. If your enemy is defending and has lots of hp, it's probably not worth spending all your stamina on heavy attacks just yet.  If your enemy is about to fall over, get to offense stance so you can drop the crushing blow on them. etc

Rarely, you'll find enemies with ranged attacks. Even more rarely, those enemies will actually back away from you to use their ranged attacks. If they get too far away from you, you won't be able to do damage with melee, so don't waste your stamina. Just use moves that say they get you closer until you're ready to hit them again.

Note that a yellow move means you'll be very low on stamina/balance after doing it, while a red move will run you out of one of the two, and you will fall prone immediately after using the attack. Either avoid red moves or make sure they finish the fight, or you're probably going to get punished for them.