See there is the inconsistency, your heart pumps faster, your breathing becomes heavier and your hands may shake when you have a monster hand or nothing at all!!
So how can you read these "tells"??
You "make" the tell by seeing their hand after exhibiting the same behaviour on more than one occasion - btw you get much much more info when you're not in a hand than when you are, when you're in the hand you want to put them on something specific to either let you in or out of the hand feeling justified, when you're not involved in the hand you are much more objective and open to reads.
Without seeing showdowns (or players that flip their hand when they don't get called) then yes, the tell is meaningless. If you're in a big tournie with long structure - pick a player and watch them every time they are in a hand for an hour when you're not (and try not to make it obvious as people change behaviour when they know they are being watched). Then switch to another and build up a mental library.
However, don't see a "tell" twice and label it as permanent, keep your mind open and be prepared to switch it off as better players switch their tells

If it swiotches then the player is aware, is probably good and therefore not worth trying to label too much, only bad/inexperienced players do the same thing over and over without trying to change it. They are the ones you are after, I know cause I've had that little fish being circled by nasty sharks feeling on more than one occasion at a big event lol
stoneii