-- Alchemy by making [relatively] expensive potions with easy to find ingredients .... IIRC the wiki and other sources have good lists for this now ...
-- Find a creature that attacks fast but doesn't hit hard and sit there and hold down the block button. [Go have dinner & come back]
-- See above but don't block so your armor ratings go up [be prepared to heal more often than with Block thouh]
-- Get a follower(s) who can train you and take back the gold from the training
-- Buy all the training you can afford ... $ shouldn't be an issue and it is relatively easy to make with Enchanting & Alchemy ...
-- Buy all the filled Petty/Lesser Soul gems you can find and fill as many as you can to level up Enchanting ... just enchant all the daggers & hide bracers you make

-- Don't use your best offensive weapons. If you have a high damage weapon you won't level up that skill quickly if you kill too fast. Use a lower damage weapon and your skill with the weapon will go up more quickly.
-- Use Soul Trap & Bound weapons & Elementals for Conjuring [OK it's not really that fast]
-- Detect Life in a "packed" Tavern may help out with alteration
-- Destruction takes spamming spells at targets ... If you have enchanted gear to lower costs that helps so you can spam more quickly ....
Oh ... don't forget to do all of the above when you're under the proper stone [warrior, mage, or theif], have just have a good solid 8 hours in your own bed with your wife so you get all the bonuses

Edit: IIRC if you have gear on that gives bonuses [like +Alchemy, Smithing, etc.] you might skill up more quickly. I know this works for Alchemy by increasing potion value but it may help with other fields ....
Nothing else fast [or lame] really jumps to mind ... I'm sure that are dozens of better examples than what I laid out though.