Is your problem
a) to realize you are tilting or likely to tilt ?
b) to make yourself stop playing when you tilt ?
c) to find a way to de-tilt so that you can keep playing ?
if you answered a), you may want to look at
biofeedback devices, although this is largely unexplored in the context of poker.
for b), just do it. If you body doesn't submit to your conscious mind, consult a psychologist.
for c), take a nap, exercise, shower ot whatever works for you. Maybe just wait a little.
Another option is to avoid situations that you know are likely to trigger tilt. For instance you might choose to play lower because the monetary fluctuations will not affect you much. I know that I usually have to stop playing after I lose a buy-in at 25/50 NL, although it doesn't affect me much at 3/6 NL. Or you can try to avoid neutral ev - high variance plays because of the implied tilt odds, which will generally mean play a little more like a nit.