In other words, how do I know if I'm really being objective?
Find out the difference between what are concepts and what is.
Follow the sensation of the breath not the idea of the breath.
Follow the sensation of the feet as they move exactly in the present moment and don't follow the idea of the feet.
Notice thoughts as they happen or as they are remembered but don't make an effort to notice or not notice the content of the thoughts.
Notice what mental content is being reacted to, notice intentions.
When you merely witness what is in attention and realize that it is what it is then there cannot be any bias in that moment. Bias comes with consepts.
One of the most powerful and useful suttas is SN12.23 Dependent Origination.. SN12.23 lists the things you can observe while being rightfully mindful of biases and inclinations. For example, suppose a seductive thought comes to mind. Then one can use this sutta to find the roots of that craving:
I say that craving has a vital condition.
And what is it? You should say: ‘Feeling.’ … You should say: ‘Contact.’ … You should say: ‘The six sense fields.’ … You should say: ‘Name and form.’ … You should say: ‘Consciousness.’ … You should say: ‘Choices.’ … I say that choices have a vital condition, they don’t lack a vital condition. And what is the vital condition for choices? You should say: ‘Ignorance.’
One can look for and relinquish the feeling (e.g., "there was attraction" vs "I liked")
One can look for and relinquish the contact (e.g., "there was a sight" vs. "I saw")
One can look for and relinquish the six sense fields (e.g., "there was a sight" vs. "I saw softly billowing hair in the sunny breeze")
One can look for and relinquish the name and form (e.g., "healthy person" vs "beautiful blonde")
In other words, use the the efforts to restrain, to give up, to develop, and to preserve
By not trying to avoid them .You let it all come, your very avoidance is recognized ,there is no certain state that needs to be achieved,because if you put that in your mind then always you will need to get to that state else you feel disconnected and thats called rapture .
The play of life is happening and at emptiness there is looking without a looker ,no conceptual understanding is forced ,the play is simply happening with all its colors .In Vipassana there is realization of that which is already happening no special state needs achievement no miracle ,just realization of the miracle that is already there ,when that realization is perfectly clear and not just a flash ,there is a new rooting in the emptiness instead of the identity and no need for methods.
As i see it When mindfully observing the arising, persistence and the cessation of phenomena one hopes to be rewarded with increase in mindfulness and or a pleasant abiding.
There is a case to be made for paying attention to inclinations and biases, taking note and adjusting by directing the mind accordingly. If one fails to take note and is just noting whatever there is it is compared to a cook not taking note of the master's preferances and inclinations.
"Suppose that there is a foolish, inexperienced, unskillful cook who has presented a king or a king's minister with various kinds of curry: mainly sour, mainly bitter, mainly peppery, mainly sweet, alkaline or non-alkaline, salty or non-salty. He does not take note of his master, thinking, 'Today my master likes this curry, or he reaches out for that curry, or he takes a lot of this curry, or he praises that curry. Today my master likes mainly sour curry... Today my master likes mainly bitter curry... mainly peppery curry... mainly sweet curry... alkaline curry... non-alkaline curry... salty curry... Today my master likes non-salty curry, or he reaches out for non-salty curry, or he takes a lot of non-salty curry, or he praises non-salty curry.' As a result, he is not rewarded with clothing or wages or gifts. Why is that? Because the foolish, inexperienced, unskillful cook does not pick up on the theme of his own master.
"In the same way, there are cases where a foolish, inexperienced, unskillful monk remains focused on the body in & of itself — ardent, alert, & mindful — putting aside greed & distress with reference to the world. As he remains thus focused on the body in & of itself, his mind does not become concentrated, his defilements are not abandoned. He does not take note of that fact. He remains focused on feelings in & of themselves... the mind in & of itself... mental qualities in & of themselves — ardent, alert, & mindful — putting aside greed & distress with reference to the world. As he remains thus focused on mental qualities in & of themselves, his mind does not become concentrated, his defilements are not abandoned. He does not take note of that fact. As a result, he is not rewarded with a pleasant abiding here & now, nor with mindfulness & alertness. Why is that? Because the foolish, inexperienced, unskillful monk does not take note of his own mind. Sn47.8
There are teachers who tell students; just note everything... when sleepy and nodding; keep noting and you wil either wake up or fall asleep right there. This instruction is fwiw contradictory to the teaching given to Maha Moggalanna in Capala Sutta. Therein as soon as the hindrance is know to be present, effort is made for it's eradication and this approach is repeated for other hindrances in the sutta and is called directed development.