Each time the big blind comes around to you, take 5-10 seconds to evaluate your tilt level. (Live games you can just hold your chips for a moment, online uncheck the autopost.) Are you still angry about a bad hand during the past orbit? If so, will it continue to occupy your mind, or can you forget it completely? If it is something that is sticking with with you, leave the table. You can always come back later.

Also, when you are assessing your tilt level, often there are physical signs that it is affecting you: hot head and sweatiness, headache, stomach flips, swearing, clenched fists/muscles, etc. You should be able to play in a relaxed physical state.

Another thing to remember is that tilt affects you in different ways. Usually we think of it as making us reckless, chasing pots we have no business being in, making massive bets/bluffs, etc. But tilt can also have the opposite effect: making us too timid or gunshy, afraid to pursue pots we should, give villains bad drawing odds, etc. We just got stacked, so no we are afraid to use our chips as a weapon because we fear losing more, so we are not playing optimally.