"The best one could possibly play given the circumstances" is (?) to always:
1) Know or being able to calculate the exact card-odds.
2) Know or being able to calculate the exact player-odds.
3) Never give a tell.
The first is (theoretically) possible. The number of cards are finite as is the number of players, so the number of combinations that could happen card-wise is countable. "Ace of hearts is dealt, then 2 of hearts, second player gets..." is one of those combinations.
If you're not doing any reading of players (by using previous life experience) the second is possible and could then maybe be called "mathematically" perfect poker. It includes using all information of how often your opponent has been folding/calling/raising and with how much.
After you calculated the percentages for you folding, calling, raising with 50, raising with 51... you need a random-number source. Randomize your next move and how long time to wait before clicking the mouse and your play will be impossible to read.
