I've never actually seen it improve from use, and I played many thieves and other classes with pick lock.

Does skill % even matter for what locks you can pick?

Lock pick is not at all random, either you succeed or fail based on some relatively static factors:: Level, Skill %, Dexterity, and quality of lockpicks.

If you lower your dexterity and have bad quality lock picks, you can guarantee that you'll fail at picking a pickable lock, giving yourself a chance to improve.

What you're looking for is a lock that you fail on, but don't get the "beyond your comprehension". Find one of those, and spam it up. If you find that sweet spot, you'll perfect it before you successfully pick the lock.

I just got any lock pick and a key for a door, and spammed unlock and pick.

It went up just fine the one time I bothered with it on my bard, and that was only to be able to pick the lock in galadon for villagers that got stuck. I generally found very little use for the skill.

Generally you need to use a crappy pick on a tougher lock. There are rusted picks easily accessible in Aldevari that are great for improving pick lock.

Most lockpicks I could find would open any lock on first try, if the lock was openable at all.

Drop your dex to make you worse at picking locks but still able to learn.

For example, if you found a lock you could pick with a really good pick and max dex, then go grab a crappy pick and work at the lock while your skill goes up. If per chance the skill gets to like 90% and you succeed in picking it, try dropping your dex a few points and you should go back to failing it until you've got it perfected.

I'm guessing this also means arials are better lock pickers than svirfs. People probably already knew this but I was surprised to find dex had a direct impact on it.

NT

If you didn't know. Pay attention to the echo. One is "you failed, try again" and the other is "You won't ever pick this." Find one of the first variety and you've likely found a lock you can pick, but your skill isn't high enough yet. Proceed to spam.

In other words, don't bother mastering lockpick. You'll do it when you find a lock.

and proceeded to spam.

You failed to pick the lock.
You failed to pick the lock.
You failed to pick the lock.
You failed to pick the lock.
You failed to pick the lock.
You failed to pick the lock.
You failed to pick the lock.
You failed to pick the lock.

...

over9000 times.

It NEVER improved ONCE.

Takes way too long.

On past thieves, I've always had trouble learning pick with really bad picks like the rusty. When I switched to slightly better picks, I began to improve. *shrug*