Well, if you already have the enchanting 100, smithing 100, which is highly recommended, then you should have lots of gold to work with. With the gold, buy all the ingredients at alchemy vendors and try to make the strongest potions by combining random ingredients. Quality over quantity. Don't make too many sucky potions to fill your inventory, it'll just waste ingredients and space. Try to go for strong potions that cost at least 400 gold. The best combo is wheat+giants toe. After all that potion making, you should have tons of potions to sell. Train your alchemy skill with some like Arcadia, and then sell all the potions you just made to get your money back.
Slap on the thief stone, and if you have a home nearby, sleep for like 1 hour. The Thief stone give 20% faster improvement and the sleeping is an extra 10% for 8 hours in game.
A good way to make alchemy vendors restock is to either wait 24 hours, or save the game, kill the vendor, and then load the game.
Hope this helped, this is what I did.