Improving Sati-Sampajañña (situative wisdom) Although one can cultivate sati (recollection/mindfulness) through meditation &amp; good conduct (silā), &amp; one can learn wisdom via book knowledge as well as via direct seeing (for example rising &amp; passing away of phenomena), how does one know (exactly) what to do/think about in every day life situations?
Improving Sati-Sampajañña is actually right samadhi. When you want to improve  "every day life situations", then you do Sati-Sampajañña. this is exactly the purpose of Sati-Sampajañña: sorting thoughts and perceptions-feelings in  the casual life, when you eat, drive a car and talk to people, before being physically secluded to do the jhanas...

Sati-Sampajañña is a bridge between sila and samadhi, especially for people who already are inclined to the sila that the buddha explains. for people who behave differently than whatever the buddha calls sila, they improve their sila by training for Sati-Sampajañña, or Satipațțhāna, ie watching their speech, their thoughts, their body movements, whatever daily life involves for a lay people...

Most people cannot hold naturally sila for more than a few days, and they can prolong that by forcing themselves, but they will fail eventually.
So they have to develop the next step to fortify the first step. The people who are already well behaved as the buddha defines it, ie at the very least the ''5 precepts'', they can go directly to Sati-Sampajañña and they will fortify Sati-Sampajañña by going further than Sati-Sampajañña, ie training for the jhanas, ie samadhi.

Sati-Sampajañña is really for everybody: bikkhus and lay people, noble ones or not.
Jhana is for people who "have gone to the wilderness, to the shade of a tree, or to an empty building" for a few hours or days, which will mostly be bikkhus, precisely because lay people prefer to be busy with something else.

Then the next step is to get the fruit of sati, proper intention, proper examination, proper samadhi, ie panna, ie to terminate the mixture of ''meritorious activities with the beginning of  investigation into ''reality'' '' that is the noble path, ie  Sati-Sampajañña, right samadhi and sila, in order to become an arahant, or at the very least a sotapanna.
You do that with carrying sati over samadhi, which would be called ''sati samadhi'', but that word does not exist in the suttas. Right samadhi is actually this ''sati samadhi''.

Is is like doing a recipe [for a say  an omelette] : when you cook, you have a result in mind and  you have raw food that you transform in order get the result you want


sampajanna is the raw food = vitakka, vedanna, sanna
sati sampajanna is (the beginning of) what you do with the raw food.


with sati you manipulate the raw food towards the direction of panna. Sati is a direction, a view, a goal where you want to go (and in this case the direction towards nibanna, panna, right view and so on).

Sampajanna is the raw food and you can do several things with that, just like you can  do several things with an egg. For instance, the people who invented vipassana mediation, they play with sampajanna, ie with thoughts, feelings, perceptions, but they go in another direction than sati-sampajanna (even though they love to claim otherwise), because they refuse to judge and remove bad vitakka, sanna, vedana from what they experience, they lvoe the idea fo ''doing nothing'' and just watching perceptions, thoughts and so on, then they claim that this watching will get you to see anicca, then fear of dissolution, then some fruition, then sooner or later first path....

then you have samadhi, which is a a better food than sampajanna, and it must still be cooked, ie manipulated, treated, influenced to get panna.
You can do several thing with the jhanas, typically you can just ''abide in the here and now'' to generate merit, or you try to reach nibanna.

People today always wonder how to combine vipassana with the jhanas. They also wonder how much active thinking there is in the jhanas (because they read the vitakka and vicara in first jhana, but nobody know what they mean). For instance, 


some people say that there is zero thinking in any jhana
some people claim that there is only active thinking  in 1st jhana, and zero thinking in other jhanas
some people say that there is active casual thinking in 1st jhana, zero active thinking in 2 and 3 jhana, but in 4th jhana, there is active thinking again, but this time, with uppekha and sati, and this thinking is  when you do vipassana
some people claim there is active thinking in any jhana


well the answer to ''how to do vipassana in the jhana'' is precisely ''right samadhi'', because the buddha says it is with right samadhi that ''seeing things as they are'' occurs, ie the samadhi which comes from right view, right intention, sati and this right view, sati, and so on carries over to samadhi:

when you watch a tv show for several days, or read a big book, or hear a music  which stays on your mind, you start saying the words that they use in the book or the tv show. Sometimes you an even start dreaming about the book or the show. or when you start living with new people, you start to use some of the words they use (and that you never ever used before). It is exactly this that is needed to convert samadhi into panna: you must carry the sati into samadhi.

With Sati-Sampajañña you saturate your ''mind'' (mano, citta, vinnana, whatever it is which memorizes and cognizes thougths) with sati, ie you think about and ponder the dhamma all the time, and this sati must carry over into samadhi, just like when you read a book for a long time, you start dreaming about it.
And whatever thinking you have in whatever jhana you dwell, the ''mind'' (typically in the jhana, it is the citta which is more important than mano or vinnana, because it is the citta which determines the next birth and the casual jhanas are all about merits and births) will have to be influenced by sati, right view, right intention which is this stuff:


  ‘The first absorption is a basis for ending the defilements.’ That’s
  what I said, but why did I say it? Take a mendicant who, quite
  secluded from sensual pleasures, secluded from unskillful qualities,
  enters and remains in the first absorption. They contemplate the
  phenomena there—included in form, feeling, perception, choices, and
  consciousness—as impermanent, as suffering, as diseased, as an
  abscess, as a dart, as misery, as an affliction, as alien, as falling
  apart, as empty, as not-self. They turn their mind away from those
  things, and apply it to the deathless: ‘This is peaceful; this is
  sublime—that is, the stilling of all activities, the letting go of all
  attachments, the ending of craving, fading away, cessation,
  extinguishment.’ 


and the result is:


  Abiding in that they attain the ending of
  defilements. If they don’t attain the ending of defilements, with the
  ending of the five lower fetters they’re reborn spontaneously, because
  of their passion and love for that meditation. They are extinguished
  there, and are not liable to return from that world.


like when you give an impulsion to a boat on a water to make the boat go forward ''alone'', sati from Sati-Sampajañña must give a momentum to samadhi. If there is thinking in the jhanas, then it is good news since it gives a new chance to influence the citta in samadhi, if the sati of Sati-Sampajañña is ''forgotten''; but if there is no active thinking, then all this influence relies on Sati-Sampajañña.

it is exactly the same thing with anapanasati: the raw food is listed as ''kāyasankhāraṃ'' and ''cittasankhāraṃ'' and you have to influence them with sati, right view, whatever wisdom and little tricks are memorized, in order to be sensitive to them and calm them until the citta is in samadhi, as per tetrad 3, instead of being distracted by rupa...

And anapanasati suffers from the same situation as the samadhi above : nobody knows what ''sankhāraṃ'' means and nobody knows what it means ''to be sensitive to the sankhāras'', in order to calm them [tetrad 3] and abandon them [tetrad 4], so you have to wait for a buddha to explain all that.