For example, wondered about basic things like can you take two potions at the same time and both be effective (potion stacking)? I've tested and it seems like only the last one taken is in effect.

Tip: One way to raise some decent gold (400-600/potion actual selling price) is to mix crazy combos like Giant Toe + Wheat or Bear Claw and Hanging Moss. I say crazy as some of the combos can have both positive and negative effects so you probably do not want to use them. Any potion of Fortify Health or Stamina (+xx/300 seconds) is in the 250-350 range.

I have amassed a stockpile of about 2000-3000 various ingredients by paying a little attention while proceeding through quests and just walking around. Most are fairly easy to accumulate. Giants Toe generally requires taking on the big guys but a potion of slow or paralysis usually makes that battle (particularly if there is more than one or one-two Mammoths) go a little easier.

I found some pretty useful info on potions at the uesp skyrim wiki. Was wanting poisons for my arrows and got some good ideas there.

Potion value and strength increase along with your Alchemy skills, and how you use perks on the Alchemy tree. You'll "discover" more combinations as you acquire more skill. Even after you reach 100 in Alchemy, you'll still discover new effects. Adding two ingredients is standard. However, adding the optional ingredient can give some nice extras--or add negitive effects. And yes, potions are 'the' way to make good coin. I'm just past level 70--and making potions worth well over $2000 per bottle (depending on what's being made), and selling them to the trader in Riverwood--he always has $10,750. I really like making poison with paralyze--shoot a Falmer with an arrow (boost your Archery skill), then run up with a mace in each hand , and beat the crap out of him while he's still paralyzed (might as well boost your one-handed skill while your at it).