Ponits are allocated in all mark schemes for contextual discussion of the text/texts. This can often mean a whole grade difference if context is used effectively, as well as enriching and polishing an essay in general terms. Contextual information can be social, political, historical or even literary theory and can often add whole dimensions and alternative readings to a text. Context can be used to link and compare texts and is a really easy way to boost your overall mark with as little as two sentences.
For me, context has often been some of my favourite research when studying a text. As a lover of history, it has enabled me to get to the root of a text and draw useful information from the author's biography and other texts and sources of the time. It is important to handle contextual information with caution as we cannot draw all conclusions from an author's biography/ history and feel that we can understand the text entirely. For example, it is too far an assumption that the unfaithful mother in Hamlet was modelled on Shakespeare's own infidelity within his marriage. You can however, argue that one reading of The Tempest sees Prospero as a reflection of Shakespeare himself, because of his references to actors, the globe and the stage in the context of the play. However it is important to realise that this is one of many contextual themes that are relevant to The Tempest, others being colonial theory, politics and power, magic in the 17th century and many more.