Thinking is like using (at least) one of my senses, but without actualizing the associated physical reality. Right now I can access memories that contain information in audio, visual, tactile and olfactory formats with little effort. I often experience multi-person conversations or music as part of a thought process, but have also known myself to mentally fly around a map, generate pseudocode, mix flavors, sketch an image, or even explore a texture as part of thinking.
...With a little reflection, I find that much of my internal process hinges on something like infographics with little sensory labels, primarily audio but often tactile or even olfactory, but hardly ever actual text. For a complex operation, I seem to zoom in and out on these objects to get the detail/context relationships and see how they interact.
Sequence index: Living Luminously
Previously in sequence: The ABC's of Luminosity
Next in sequence: The Spotlight
You should pay attention to key mental events, on a regular and frequent basis, because important thoughts can happen very briefly or very occasionally and you need to catch them.
You may find your understanding of this post significantly improved if you read the third story from Seven Shiny Stories.
Luminosity is hard and you are complicated. You can't meditate on yourself for ten minutes over a smoothie and then announce your self-transparency. You have to keep working at it over a long period of time, not least because some effects don't work over the short term. If your affect varies with the seasons, or with major life events, then you'll need to keep up the first phase of work through a full year or a major life event, and it turns out those don't happen every alternate Thursday. Additionally, you can't cobble together the best quality models from snippets of introspection that are each five seconds long; extended strings of cognition are important, too, and can take quite a long time to unravel fully.
Sadly, looking at what you are thinking inevitably changes it. With enough introspection, this wouldn't influence your accuracy about your overall self - there's no reason in principle why you couldn't spend all your waking hours noting your own thoughts and forming meta-thoughts in real time - but practically speaking that's not going to happen. Therefore, some of your data will have to come from memory. To minimize the error introduction that comes of retrieving things from storage, it's best to arrange to reflect on very recent thoughts. It may be worth your while to set up an external reminder system to periodically prompt you to look inward, both in the moment and retrospectively over the last brief segment of time. This can be a specifically purposed system (i.e. set a timer to go off every half hour or so), or you can tie it to convenient promptings from the world as-is, like being asked "What's up?" or "Penny for your thoughts".
When you introspect, there is a lot to keep track of. For instance, consider the following:
You cannot have too much data. (You probably can have too much data in one situation relative to how much you have in another, though - that'll overbalance your models - so make a concerted effort to diversify your times and situations for introspection.) When you acquire the data, correlate it to learn more about what might bring various aspects of your thought into being.