As a moderately useful skill (it gets you more money, which is good and lets you intimidate/bribe/persuade) I just have a few observations for people interested in advancing the skill. Of course the skill advances when you make a intimidate\bribe\persuasion attempt, it increases by more if you are successful, but either way you get a gain. The other, natural, way to increase the skill is to sell items. Skill increases based on the value of the item you are selling, but all transactions for 1 gold or more increase the skill. Some simple tricks to leveling the skill faster involve using this feature.
- Lockpicks and arrows have no weight and are plentiful (plus if you are using the Skeleton Key\Unbreakable Perk you don't really need all those picks), arrows are especially easy to get. Iron, steel, and forsworn arrows can be found in abundance. When you have a hefty stash (I don't recommend keeping hundreds of them, the reason why will become evident later on) goto a merchant and begin re-selling them. When you sell them be sure to sell them one at a time. I know it is time consuming, but this is how the skill works: When you sell a bundle of 50 arrows, it counts as one transaction for the value of just that one item. That means you lose out on 49 other opportunities to get a few points into the speechcraft skill. This of course works best with expensive arrows and since much of the damage done by a bow is determined by the bow itself you may want to sacrifice those elven, ebony, and glass arrows (or even daedric) to get some bonus points in speechcraft. This works great for potions too, unfortunately potions tend to get heavy very quickly, but if you just pick up every potion you find worth more than say 100 gold you can get some fast skill gains when you re-sell them.
So moral of the story: Take the time and sell off your loot individually!