The concept of foregrounding is an interesting one that emerged from the critical school of Russian Formalism, the proponents of which relocated to Prague when Stalin determined Formalism to be a literary "heresy." In reaction to the literary theories that preceded, which lacked rigorous standards and guidelines, Russian Formalism undertook a scientific examination and description of the literary devices that comprise literary language and make it distinct from non-literary language. An important component of this literariness associated with literary language is the concept of foregrounding.
Foregrounding is the use of devices, most notably patterning (e.g., repetition), ambiguity, diction, metaphor, tone, parallelism, along with theme, character and plot, to create defamiliarization through linguistic dislocation, a concept that opposes the preceding theoretic position that literature reflects the world. In other words, the formalist concept of foregrounding, further developed by Jan Mukařovský, asserts literary language creates a "making strange" that puts the world in a new perspective that opposes a theory of a reflected perspective. Mukařovský's concept of aktualisace, translated as foregrounding, focused on the use of devices to emphasize what Formalism considers nonreflective features, elements, or concepts associated with literary language.
Having thus laid the groundwork, it is clear to see how foregrounding, though the concept and its notions were unknown to early writers, is an important stylistic element for creative writers going back even to Homer. In Homer's Iliad patterning is a prime device as he repeats passages and descriptions that are of paramount importance to understanding the lives of the characters, for example, "strong greaves," and "greatest kindness." Diction is a paramount element to both Edmund Spenser and Shakespeare. In addition Spenser produced a brilliant example of patterning in his Epithalamion. Metaphor wis an inseparable part of literariness in literary language for the Romantics and continues so today.
Foregrounding, this major component of creative writing, this linguistic technique that dislocates language into defamiliarization, is and has been a major stylistic device through all ages--which incidentally corroborates the validity of the approach of Russian Formalism.
Foregrounding is a deviation from the norm in artistic communication which emphasizes certain features of a work of art at the expense of others. The term was developed by Murakovsky and Jakobson who found the technique particularly consistent and systematic in literature. Yet, Geoffrey Leech in his standard text A Linguistic Guide to English Poetry finds that foregrounding also works in other artistic fields such as painting and music. According to Leech, a representational painting is interesting for its deviancy from photographic accuracy, while an abstract painting deviates from regular patterns of composition.
There are different foregrounding techniques which all aim to create a sense of surprise and unexpectedness from the audience. Leech quotes as example the mixture of registers found in the poetry of the modernist Pound and Eliot. More everyday examples are widely found in advertising and include the alternate spelling of words such as Krazy for crazy.
The following links provide more examples