I was reading about pot odds because I realized I wasn't actually calculating them. I read something that said you account for all unseen cards. I have been counting off of how many cards are left in the deck.

Say I am trying to count my flush draw, do I count unseen cards or cards in deck?

you count all unseen card - since you don't know what cards opponents have/had or what cards were burned, any distribution among them is equally likely. So, if you are drawing to a flush (9 outs) and know you hand and a flop (5 cards), your chances to get there on the turn are 9/47, which is roughly 19%

I'm gonna be a little anal here ... POT odds have nothing to do with cards, seen or unseen. Pot odds are the ratio of the 'call' to the pot, including the 'committed' chips of the bettor or anyone else still in the hand who has already acted.

Unseen cards (outs) are used to calculate the EQUITY you 'may' have left in the hand.

Players compare Pot Odds to Equity when considering a call.

In your thought process you 'may' be able to eliminate some of your equity (outs) by the way other Players act when they fold or your own impression of what they might have held in their hand based on how you range them. If you've gotten to the Turn 4-5 ways and the Board is super wet/draw heavy then it's safe to assume that at least some of the Players in the hand 'share' cards, which makes them less available to hit the River and improve your hand (or more importantly, improve any remaining Player's hands if you think you are ahead). This affects your 'true' equity but not the Pot Odds you face to call ... those never change once action is on you. GL