8. Failure to read what is happening in another's soul is not easily seen as a cause of unhappiness: but those who fail to attend to the motions of their own soul are necessarily unhappy.
9. Always remember these things: what the nature of the Whole is, what my own nature is, the relation of this nature to that, what kind of part it is of what kind of Whole; and that there is no one who can prevent you keeping all that you say and do in accordance with that nature, of which you are a part.
In order to exercise the discipline of assent, you must circumscribe yourself. What does that mean? It means you must define and clearly make a limit or boundary around your mental state. Marcus Aurelius uses the imagery of a citadel. If your mind in in that citadel, you control what is in it (your attitude) and everything outside of that citadel is out of your control.
In the domain of things outside of your control are things such as other people, the past and present and then those involuntary emotions that happen to our body. Another thing outside of our control is the course of events or the course of destiny (see pp 115-118 Inner Citadel).
To further this image, think of a citadel and then look at it from above and see various domains of things outside our control ... similar to a target.
When it comes to the discipline of assent, you must constantly determine what is in your control and what is out of your control. Furthermore, you must make an effort to view events and externals objectively - that is; do not add your opinion (automatically) on top of events. Let there be a pause or space between the external and you forming an opinion about it. Another term of this is mindfulness.
In verse 7, Marcus cautions against distractions and drift. To counter this, give yourself space ... give yourself some time to think before reacting or having a strong negative or positive emotion.
In verse 8, we must observe what is happening in our own soul. If we don't observe what is happening in our own souls, we will be swept up in external events (we lose our control).
Lastly, in verse 9, he is advising that we should constantly be mindful of our position in relation to the whole. This is a theme that comes up again and again in his Meditations. We are a speck in the Universe and we ultimately have control over our attitude and how we perceive the world.
How do you become more mindful?
You meditate - it's as plain and simple as that.
How do you meditate?
There are lots of options and ways. Regardless the method, what you are trying to aim for is the ability to pause and reserve judgement on things and events. You want to get away from the automatic response. It is not easy.
Some will sit in solitude and just observe their thoughts. Others will concentrate on a single thought and not let their mind wander. But again, no one way is correct. Rather if the way you meditate helps you have greater control over that pause, then it is working.