Jesus Christ. Tried to start levelling my Nord's alchemy skill last night. Holy crap. I seriously have no idea what I'm doing. I made one good potion from a giant's toe and some wheat, but that's it. Do giants respawn? Cause next time I play I'm going to wage genocide on the giants of Skyrim for their toes.

Try blue butterfly wing and blue mountain flower.

When I start levelling alchemy on a new character, I usually first get as many ingredients as possible by gathering and buying them (doing a favors for the alchemists is a good idea, since they will let you take most of the ingredients in the shop after that). I don't buy the expensive ingredients at first.

Then I eat one of each ingredient to learn at least one thing they do.

When I start mixing, I always add a third ingredient, to learn faster. I sell what I can to the alchemist, get new ingredients, start over (there, or at another alchemist).

try making potions of invisibility, seek out the ingredients and make as many as you can, they seem to be worth more than other potions, exp.-wise.

keep an eye out for:

Vampire Dust,
Chorus Eggs,
Luna Moth Wings,
Ice Wraith Teeth
Nirnroot and Crimson Nirnroot.

http://www.gamesas.com/topic/1420293-alchemists-post-your-recipies/page__fromsearch__1d. It should help you in making some powerful potions and poisons, as well as making you a ton of dough.