How do you know your breathing technique is correct?

One of the easiest ways to know is to monitor your heart rate. If you are breathing and meditating, your rate should be going down after 6-12 breaths.

I know my breathing technique is correct when every breath is no longer or shorter than the previous one. It's just natural and you can feel the air coming through your body thorough your nose.

When practicing relaxation techniques, I try to focus on how I am feeling during and after the exercise. For my breathing technique during the week, I breath in through the nose and exhale slowly from the mouth. Concentrating on the slow exhale works for me.

When you inhale to you belly first, followed by the chest and then expand the areas between the shoulder blades and then we exhale through the nose we have become three part breathers

I learned it during an intensive study if Ashtanga yoga, but ethos aside I know it's right because it makes me feel divine and lowers my heart rate to 50bpm

It's not. But I'm working on it. I breathe mindfully more and more times through the day. As I wait, when I'm in a different spot or an awkward position/moment. Less mouth, more nasal. Counting, placing hands different spots thoracically to check expansion and exhalation. Trying to gauge what's up/new/different/ going well with my exercises & experiments. Watching YouTube for new/better information, trying to build in little minutes of improvement and practice.

There are many different breathing techniques, I start off trying different techniques under guidance using apps like Yogaglo, MindValley, YouTube until I find one that I like. I follow instructions and usually if the instructor is good I feel confident I’m correct. Once I feel confident I can practice on my own, but like to revisit guided breathing to make sure I haven’t slacked off and use a refresher!!!

I don’t think it has to be “correct.” I focus on being mindful, not breathing exactly a certain way. Doing practices that are too procedural or prescriptive about the breath makes me anxious, so I avoid those.

I use a meditation app. It helps to remind me to sit comfortably and focus on my breathing. I breathe in and out of my nose and become aware of the rise and fall of my diaphragm.
I body scan and where there are knots of tension I comb them out in my minds eye. More importantly for me is ensuring I don’t get swamped my extraneous thoughts and I clear my mind.

I have an Apple Watch so I have an app for breathing, but if you just sit and relax then your breathing will be natural, and that is correct. It’s important to relax your body and muscles and just breath naturally.

I use a technique that I was taught in a yoga class. Breathe in thru your nose for 7 counts and out through you mouth for 8. When filling your lungs, think about filling your abdomen too. Expel all the way through your abdomen as well.

Breathing is an unconscious task and we are well programmed to do it. However, for a good deep breathing (especially before meditation) I help me using a metronome.

I use the breathing square technique when I want to ground myself. Breathe in to the count of four, hold for the count of four, breathe out to the count of four and pause for the count of four. Repeat as needed.