Being new to this game I'm still working out the game mechanics. I know that using your skills obviously improves them, but how relevant must that use be for it to impact the skill increase? Like if I run around and jump up on rocks etc. my Acrobatics and Athletics increase, but it seems like Sneak is only considered used effectively if someone is around and you sneak past them. Similar for Marksman, hitting an enemy increases you skills, but as I went to the Arena and took some practice shots on the target there, I didn't notice any increase in my Marksman skill.

So my question is: Which skills can be trained, and how?

You have to hit a living target, otherwise it doesn′t count. Same goes for sneak, someone has to be nearby and not detecting you for that skill to increase. When you lockpick you have to succeed setting a tumbler in place in order for that skill to increase and so on

That's not entirely true. I nailed a bandit with my bow, which took two arrows, but I had already drawn the third just in case. After he went down I didn't know how to put that arrow back in mu quiver (I still don't btw) so I walked over to him and put it next to the other two in his chest. That increased my Marksman skill, even though this dude had been dead for over 30 secs. So unless dead bodies count as living targets, there must be something else to it.

And apparently spamming spells at random with no target or real use increases your skill too, so not all skills have to be used effectively.

Sounds strange, never happened to me that hitting dead persons increased my skill. But it happened to you so I guess it does.
And yes, using spells does increase your skill without the need for a target. At least to my experience I better add

Destruction Spells have to hit a target.

That's sorta why I was looking for a list of all skills with a note of what you have to do to increase it =). But I guess I'll have to learn as I go.

It is actually much more fun to dig stuff out on your own. Welcome to Cyrodiil

To address the first issue about the bandit: The third arrow did not increase your marksman skill. What happened was either the first or second shot increased your Marksman skill to the next level but the message was delayed because you were in the middle of an attack (since you had already drawn the third arrow before the second hit the bandit).

To address the issue about the spells: You can spam spells at random but they have to affect a Target in order to gain experience, meaning if you spam random spells that have On Self as the Target then you'll increase your skills.

See http://www.uesp.net/wiki/Oblivion:Increasing_Skills#Acquiring_Experience_Points page for more info.

Ah, that's exactly what I was looking for. Thanks, and happy gaming!

About the arrow that you nocked:

When you are below level 50 in Acrobatics, I often fire the extra arrow into the ground in front of me, and catch it either bouncing off the floor, or retrieve it after it sticks in the ground. If you are very very quick, you can fire an enchanted arrow into the ground or floor, and quickly grab it before it disappears. I am successful maybe 75% of the time.
When you reach level 50 in Acrobatics, you gain the ability to do some dodge moves. I find these invaluable in melee combat, but a special bonus is this:

If you have an arrow nocked, and combat is done, dodge while shooting the arrow. The arrow will remain in your inventory, never having been fired, though you WILL hear the shot being fired. This is extremely useful if you have added poison to your shot, combat unexpectedly ends, and you are left holding a "live" potion that could be wasted. Simply use a dodge move, and you will have saved that poison for the next battle.

Its a bit of a glitch I am afraid, you only gain skill poists after you stop an action or series of actions within combat,
so as long as you keep swinging or holding the arrow knocked your skill will not likely increase..

If you get knocked back, or release a bow and wait a split second it allows the game to catch up with your actions and record your skill points.
This is why in combat at low levels when fight without pausing on the highest difficulty your level 5 combat skills will spam up a couple of points in my experience, rather than moving up by one while I swing away.

Edit: DOOOOOH got ninja'd!!, and more elegantly put too, note to self read everything posted first.

I didn′t know this, thanks :tops: