In between lessons with a teacher, it is very useful to keep up with the practice on your own. You can remind yourself of what you learned by refreshing the thoughts that helped bring your system into balance. It's not the same experience as working with hands-on guidance but it does make the lessons more effective and students tend to progress more quickly. Self-practice of Alexander Technique looks at various procedures and very simple activities. These are not considered exercises, which are typically done with a lot of effort and little awareness but quite the opposite. We're practicing: less effort and more awareness.
One of the best things you can do on your own, is called Constructive Rest or semi-supine, or simply 'a lie down'. Regardless of the name (a rose by any other name would smell as sweet!) what Alexander teachers consistently encourage is:
-Give yourself some time in a quiet, comfortable space free of distractions.
-Lie on a firm, flat surface, with knees bent, head supported by a few thin books.
-Let your eyes be open with soft focus.
-Let your breath move in and out.
-Do nothing for 10 min or so.
That's the most bare bones gist of it, and one the most fundamental pieces of the practice. There is more to it, some specifics and details, but since it can be easy to overwhelm at first, starting here can be enough for anyone.
Simply making some time with nothing to do, can seem impossible to many modern humans. I suggest trying 10 minutes to start but ideally work up to 15 minutes. If it is too challenging start with 5, it may take some practice to let yourself alone with nothing to do. Disconnecting from digital devices can be surprisingly provoking. This is a nice way to remind yourself how you think without it and revise who's in charge of that dynamic.
Just the act of letting yourself lie on a firm, flat surface will allow for a general decompression of the spine. Have you ever heard how we're a little taller in the morning than in the evening? The wear and tear of the day takes us down, being horizontal helps to let the discs plump back up. A floor, yoga mat, towel, rug all are fine. Mattresses and couches are not as they are meant for sleeping and do not provide the feedback we need. Use a couple paperback books as a firm (not hard) pillow so your head is supported and your neck can take a break.
You'll notice with legs fully outstretched (supine) that there is a lot more curve to the lumbar area, bending the knees gives the low back the space needed to decompress. Avoid pushing it flat, even the tiniest bit. That isn't the goal, and there is no work or effort required in non-doing.
We practice with your eyes open, because this is meant for everyday life. Staying present in your senses helps prevent a wandering mind. And vision is integral to balance and orientation. Many mindfulness practices encourage an inward focus, on breath and thought exclusively, for example. However Constructive Rest is an embodied mindfulness. When we reconnect to ourselves and the environment simultaneously our whole system responds and organizes innately.
Leave your breath alone, and let it move. No need to do anything specific, in fact, try not to! Just don't hold it and observe how it flows in and out. Breath will always move if we don't stop it.
Keep it simple and give it a try! Try it several days in a row and see what comes up for you. The less expectations you have the better, the more open you may be to a new experience.