To (re)build a bearable world one needs a portable picture of it (a picture most of the sane people would agree with), so one needs some general principles.
Yes, (any) god was a kind of general principle, but the human translators (priests, theologists) abused the concept, so we got better than that: while miracles don't happen (tricks do), science seems to have helped a lot in that direction, it works more in accordance with some general rules of nature, and is seeking and checking on them actively. And what better general principles can we have other than those that follow the nature, humanity's given context?
The first principle that seems necessary for our world is sustainability: any action we do should not consume irreversibly a limited natural resource (a non-renewable resource). There are at least two immediate and practical consequences following from this: a. using personal cars on a daily basis in a non-farming environment is a crime unparalleled in history and has to stop now! b. the amount of natural resources a person can control, or dispose of, should be reasonably limited; this, of course, implies that the total wealth of a person should be limited to what is necessary for a human lifetime (say, a lifetime of average wages).
Now that we know what sustainability means (we can live and let others, now or tomorrow, live too) what do we have to minimally do in a sustainable context?
First, the basic public/common education is necessary, which amounts to explaining to everybody what sustainability means and how to produce renewable resources that living humans consume, this implies imposed literacy and work.
Next, there's the public/common social education: it should become clear to those educated in this process that an individual can be a human only in a human context and that humans are a single species. This should qualify the candidate for human rights, before that, he's covered by animal rights only. This has some immediate consequences: a. whether you're a woman, man, black, white, yellow, blond haired or not, hazy eyed or not, you're a human and these agreed upon principles apply to each of us without distinction. b. there is the need of a common infrastructure for a functional society, that is the State, which is not under the control of any specific individual, but is there to administer what humans in a given geographical area have in common: the street between my apartment and your apartment, the water pipe that passes through my apartment and your apartment, the sewage, the language etc. Briefly: the State is the administrator of public domain, or common domain. c. the rules of administering the public domain, and the individuals' interaction with it, make a collection which is called Law. The Law is the explicit agreement reached by a majority of individuals in a State. d. each of us need to do some work to live, that is called property; the social rule is that no one can use somebody else's work without public or individual consent. e. from a. and b. it follows that living in the society of humans means that individualism has to be tempered f. it also follows from a. and b. that individuals should always be educated and have the instruments to check the activity of the State they use in common. This implies that education is common, is public. g. a population might be using a common language, that population is called a Nation. Nations might have histories, it may be useful to try to understand them. h. a set of Nations might have trouble communicating because they're using different languages, therefore a platform for a common understanding between Nations should exist, that can be called United Nations; no part of this common platform can have special decision powers, any United Nations decision has to come from a majority of the Nations that are part of it.
Work can be hard or uncomfortable, so, beside education, people need knowledge so that the work necessary to create/gather resources for their living gets easier. It's not about the "knowledge" of bullshitting others into doing your work, that's trickstery, it's about the knowledge of doing it yourself.
So the next principle becomes necessary: knowledge is not work but
meta-work, and, as such, it cannot be the property of anybody. Knowledge is not a protected resource because it is renewable and the Law cannot be concerned with it in any way because such a concern is unsustainable. So if you get to know something and you don't share it, good for you, let it be your secret, but once you share it or use it, nobody else can be constrained to ignore your actions (e.g. not to learn from them).
Another principle: Living without being healthy sucks. This means your health is a public issue: even if your sickness is not infectious, it affects your social context. A public issue is handled by the State so health becomes the State's responsibility. Other groups are welcome with health initiatives/actions, but the State is the basic handler of health: through public education and public health services.
And another one: resource exchange between two (groups of) people means exchanging
the amount of work one group/person performed (not 'will perform') with
the amount of work the other group/person performed (not 'will peform'), which should be equal when measured using a portable metrics. Anything else is not really exchange but theft. Today's money is not a portable metrics: it's not clear at all what proportion of a monetary unit stands for the physical work performed to produce an item, which part covers the contextual consequences of producing the item to be exchanged and which part, if any, stands for the reason to produce that item. Exploiting somebody's ignorance is a crime against humanity: one can ignore an ignorant but one can not exploit the ignorant and also preserve its own human quality in the process.
Communication principle: a communication infrastructure (fit for writing, reading and speaking), such as the Internet today, is a public service provided by the State, like public sewage.
Memory principle: any decision taken in the State activities is recorded, time-stamped and available for public searching and reading in a comprehensive way.
Election principle: there are no politicians to be elected, instead, the population creates an electronic wish-list and votes priorities, the civil servants implementing the State take their decisions based on items and their priorities on that list, their own administrative positions are part of that wish-list. This way, "elections" are continuous, they happen when needed.
Given these general principles, and a very few others, I think the rest will essentially fall into place.