I read on wikia that skill improvement depends only on the base damage of the weapon. It does not depend on damage improvement from smithing or enchanting.

If that's the case, the best way to improve one-handed skill quickly is to use unimproved daedric dagger because it swings the fastest whenever you are in a "safe" combat situation? It will take most hits to take down the opponent.

Can someone confirm this, please?

It's quite right. I used a dagger to level-up quickly. Apart my enchanted weapons I had a simple iron dagger to use against low level enemies for that purpose.

But... I thought daggers didn't benefit from one-handed?

I just kill people, it will go up eventually. I reached 100 rather quick.

Attacking with them will still improve your 1H skill even if the perks are fboxrd.

I always found one handed to be one of the slowest skill to level up. Going up against higher level enemies is always the quickest way. I tend to do it in tombs with draugr deathlords, when it gets over 90.

The two times I got that silly glitch where it reverted my One-Handed down to like 20 and highlighted it red, I went to Riverwood and wailed on Hadvar for a minute or two with my daggers to level it up. The skill leveled quickly but it didn't stop me from feeling like a terrible person.

Fortify One-Handed enchants do not affect daggers, but the Armsman perk does. Also note: the Bladesman perk specifically says swords, so it does not include daggers.

No. Armsman perks do not help daggers either, but the skill points give you 0.5% increase per level. But it's cool because daggers get ridiculous and awesome 30x bonus for backstab. Fair trade, I'd say.

Edit: Armsman perks do help daggers. Sorry about that.

15% without the DB gauntlets, right? But that's only backstab. We're talking about using a dagger as your melee primary. If it's only viable when attacking from sneak, then the dagger is just a specialized item in the assassin's toolkit and not really a rewarding primary melee choice.

I maxed it out before I even beat the main quest.

Just use it consistently, and it'll go up. Skyrim's not exactly a hard game.

I apologise, ever since you posted this thread I have tried my hardest to resist but I'm afraid I can do so no longer.

Try using a one-handed weapon.

Phew, got it out of my system.
As you were people...

Yeah, in my current character, I started out with two-handed weapons and was switching to one-handed at level 35.

Armsman perk does affect daggers.

I'm at 78 and trying to get to 80, so I can take my 5/5 damage perk at the root of the tree. I'm having a hard time getting it to move up. I'm considering training, somewhere. Companions are no help. Grelka is out too. I guess her skill level is too low. You're right--progress at the higher levels is sssllooowww.

i rarely use anything but one handed weapons. the other hand uses magic usually.

i somehow get the idea that the skill goes up with damage dealt to the enemy. the more hits the better.

so use an unsmithed weapon on low level enemies to get the best chance to raise the level.

Oops sorry about that. I was confused. Armsman perk does affect daggers.

Just a side not...
If you want to level up a combat skill, leave the followers at home.

I always considered daggers as a last stand weapon, that's why everyone carries daggers in addition to a primary weapon. A few special daggers (such as Valdr's) might be a decent primary weapon at lower levels, but they don't do enough damage after a while.

But the OP was looking at how to level up one-handed, so it looks like daggers are the way to go.
This is what made me think of Valdr's Dagger - it improves your crit hit chance (extra damage). While it doesn't directly add damage, it improves your overall average damage.

Edit: This is going off of my understanding that it's the base amount of damage the PC does (before damage enchantments, potions, and perk bonuses are applied) that determines the XP, not the base damage of the weapon itself.

Edit2: It's called Valdr's Lucky Dagger. I missed the R in my post and have edited to correct that.

I find that daggers as a primary melee weapon makes for a more interesting archer/assassin character, especially at higher levels when archery becomes so ridiculously powerful. As for daggers being a last stand weapon, Valdr's will smith up to something like 125 dmg without exploits.