For the lack of a self-grown definition of what Commoning is, please allow to pass word to others who thought about this subject before. Reviewing the English Wikipedia page on Commons for Commoning brings about the following statements by more reputable sources than us.
The author David Harvey as presented on the page for Commons under the headline Commoning as a process 
and sees the practice of Commoning in a field of relations within a group and a shared livelihood.
> The common is not to be construed, therefore, as a particular kind of thing, asset or even social process, but as an unstable and malleable social relation between a particular self-defined social group and those aspects of its actually existing or yet-to-be-created social and/or physical environment deemed crucial to its life and livelihood. There is, in effect, a social practice of commoning. This practice produces or establishes a social relation with a common whose uses are either exclusive to a social group or partially or fully open to all and sundry. At the heart of the practice of commoning lies the principle that the relation between the social group and that aspect of the environment being treated as a common shall be both collective and non-commodified-off-limits to the logic of market exchange and market valuations.
The author Silvia Federici is referenced further down under the headline "Feminist Reconstructions" of the Commons and seeks a form of common subjectivity in living relation to our livelihoods.
> The process of commoning the material means of reproduction of human life is most promising in the struggle to "disentangle our livelihoods not only from the world market but also from the war machine and prison system". One of the main aims of the process of commoning is to create "common subjects" that are responsible to their communities. The notion of community is not understood as a "gated community", but as "a quality of relations, a principle of cooperation and responsibility to each other and the earth, the forests, the seas, the animals.
In the introduction "How We Can Bring About a Language of Commoning" from the book Patterns of Commoning the author Silke Helfrich presents practical aspects from everyday Commoning.
> The way in which we imagine and model a system has a direct bearing on how we conceive its creation, structure and character. > > So commoning does not simply succeed when all the factors and conditions have been optimized and all institutions comply with the stipulated design principles. Ostrom herself emphasized that ultimately there is no reliable chain of cause and effect.
> While suitable institutions can provide frameworks for cooperative institutions, patterns of commoning contribute to developing concrete skills _within_ these institutions, providing sharper definition to the as-yet undertheorized concept of commoning. It is important to address the internal, intersubjective dimensions of commons because abstract terms detached from concrete practice are not well-suited to communicating dynamic social phenomenon that have many of their own idiosyncrasies.
> Ostrom’s approach should be enriched in the medium term by two complementary tools: a pattern language of commoning … and a pattern language of a “commons-based society,” which has yet to be developed.
> It is this performative creation of meanings that generates values in a community. One could call this creative process the essence of commoning. In other words: We act, and through our actions, we generate the criteria and standards through which we can ascribe value(s).
> Accordingly, values do not exist _before_ commoning as some kind of predetermined blueprint. There is no god, no state and no purportedly objectifying process that can _set_ the values of a commons in advance.
> To enter into commoning is to search for patterns that help to shape our way of living together as voluntary experiences, free from external coercion and constraints. Free cooperation as a basic principle is not only for small size communities; all of society can ultimately only be maintained if in principle cooperation can also be taken away or given up.