Basically the tip is: find some way of playing a sound every fifteen minutes or so, and when this happens, check my posture. I have found this useful for better ergonomics and posture while using my computer.
I'm using the Mindful Mynah app on Mac, and have it set to chime every fifteen minutes or so. When I hear the chime, I quickly check my posture and often find that I can improve it. I think this increases my mindfulness of how I type and sit, as the bell reminds me to check it more often. Even without the bell, I realize that I have incorrect posture more often. The nice thing about automating this process is that I just need to have the intention to have better posture once, and then I can automatically lock in that benefit over time without needing to expend much effort.