or three servings (like three 8oz servings of Cell-Tech or something?)
creatine's "results" come in the form of not getting as tired during your workout.
You have to understand the biology of muscle contraction to understand what creatine does, and thus how to 'tell if its working'.
basically your body uses calcium to start a muscle contraction by forming a bond between two parts of teh muscle tissue that sorta look like a ladder. the rungs on the ladder are where this bond forms.
creatine breaks that bond so that the muscle can contract up to the next rung, where creatine again breaks the bond, allowing calcium to form another bond on the next rung.
If you don't have enough creatine to break the bond, you won't be able to contract the muscle through the full range of motion.
In other words, you'll 'know' the creatine is having an effect because before you start using it, you'll hit failure on rep 8, but after saturating with creatine, you'll be able to push 10 or more reps on that last set.
that then translates into a better workout. if your diet and recovery are good, then it can further translate into better gains in size, strength, etc.
if you take creatine and don't do anything, it doesn't do anything either except lighten your wallet.