Get curious. Notice how you feel after you've had a particularly bad day. How long does it take for you to recover? Do you recover? Perhaps you don't know how to diffuse the stock-pile of cortisol that is accumulating in your system?
Notice when you feel good. What variety of emotions and feelings would you use to describe how you feel? How do you sustain it?
Notice if you have any little habits that kick in when you are worrying or obsessing, aka stressing; often it's your body speaking for you, well before you are aware of something that is distressing you. For example, you might be twirling your thumbs, which could be an indication that you might be engaging in some stress-inducing thinking. Looping thoughts go round and round, when they will stop nobody knows. Until you notice that you are doing it, know what to do to put the brakes on and practice your new target behaviours.
Notice when you have more aches and pains. More headaches and gut aches. What about when you are more tired or frustrated? You're mining for information, which you can put to good use to help you live better.
It's important to start the practice of noticing, without judgement. If you beat yourself up about why you did or didn't do something it may very well trigger the stress response.
As I mentioned earlier in this A-Z series, developing an awareness is a key component in undressing your stress.
Notice and learn. Notice and change. Notice and celebrate.